[RISCV] Hard float ABI support

The RISC-V hard float calling convention requires the frontend to:

* Detect cases where, once "flattened", a struct can be passed using
int+fp or fp+fp registers under the hard float ABI and coerce to the
appropriate type(s) * Track usage of GPRs and FPRs in order to gate the
above, and to
determine when signext/zeroext attributes must be added to integer
scalars

This patch attempts to do this in compliance with the documented ABI,
and uses ABIArgInfo::CoerceAndExpand in order to do this. @rjmccall, as
author of that code I've tagged you as reviewer for initial feedback on
my usage.

Note that a previous version of the ABI indicated that when passing an
int+fp struct using a GPR+FPR, the int would need to be sign or
zero-extended appropriately. GCC never did this and the ABI was changed,
which makes life easier as ABIArgInfo::CoerceAndExpand can't currently
handle sign/zero-extension attributes.

Differential Revision: https://reviews.llvm.org/D60456

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@366450 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Basic/Targets/RISCV.cpp

@@ -65,9 +65,18 @@ void RISCVTargetInfo::getTargetDefines(const LangOptions &Opts,
   Builder.defineMacro("__riscv");
   bool Is64Bit = getTriple().getArch() == llvm::Triple::riscv64;
   Builder.defineMacro("__riscv_xlen", Is64Bit ? "64" : "32");
-  // TODO: modify when more code models and ABIs are supported.
+  // TODO: modify when more code models are supported.
   Builder.defineMacro("__riscv_cmodel_medlow");
-  Builder.defineMacro("__riscv_float_abi_soft");
+
+  StringRef ABIName = getABI();
+  if (ABIName == "ilp32f" || ABIName == "lp64f")
+    Builder.defineMacro("__riscv_float_abi_single");
+  else if (ABIName == "ilp32d" || ABIName == "lp64d")
+    Builder.defineMacro("__riscv_float_abi_double");
+  else if (ABIName == "ilp32e")
+    Builder.defineMacro("__riscv_abi_rve");
+  else
+    Builder.defineMacro("__riscv_float_abi_soft");
 
   if (HasM) {
     Builder.defineMacro("__riscv_mul");

lib/Basic/Targets/RISCV.h

@@ -87,8 +87,7 @@ public:
   }
 
   bool setABI(const std::string &Name) override {
-    // TODO: support ilp32f and ilp32d ABIs.
-    if (Name == "ilp32") {
+    if (Name == "ilp32" || Name == "ilp32f" || Name == "ilp32d") {
       ABI = Name;
       return true;
     }
@@ -105,8 +104,7 @@ public:
   }
 
   bool setABI(const std::string &Name) override {
-    // TODO: support lp64f and lp64d ABIs.
-    if (Name == "lp64") {
+    if (Name == "lp64" || Name == "lp64f" || Name == "lp64d") {
       ABI = Name;
       return true;
     }

lib/CodeGen/TargetInfo.cpp

@@ -9188,25 +9188,44 @@ static bool getTypeString(SmallStringEnc &Enc, const Decl *D,
 namespace {
 class RISCVABIInfo : public DefaultABIInfo {
 private:
-  unsigned XLen; // Size of the integer ('x') registers in bits.
+  // Size of the integer ('x') registers in bits.
+  unsigned XLen;
+  // Size of the floating point ('f') registers in bits. Note that the target
+  // ISA might have a wider FLen than the selected ABI (e.g. an RV32IF target
+  // with soft float ABI has FLen==0).
+  unsigned FLen;
   static const int NumArgGPRs = 8;
+  static const int NumArgFPRs = 8;
+  bool detectFPCCEligibleStructHelper(QualType Ty, CharUnits CurOff,
+                                      llvm::Type *&Field1Ty,
+                                      CharUnits &Field1Off,
+                                      llvm::Type *&Field2Ty,
+                                      CharUnits &Field2Off) const;
 
 public:
-  RISCVABIInfo(CodeGen::CodeGenTypes &CGT, unsigned XLen)
-      : DefaultABIInfo(CGT), XLen(XLen) {}
+  RISCVABIInfo(CodeGen::CodeGenTypes &CGT, unsigned XLen, unsigned FLen)
+      : DefaultABIInfo(CGT), XLen(XLen), FLen(FLen) {}
 
   // DefaultABIInfo's classifyReturnType and classifyArgumentType are
   // non-virtual, but computeInfo is virtual, so we overload it.
   void computeInfo(CGFunctionInfo &FI) const override;
 
-  ABIArgInfo classifyArgumentType(QualType Ty, bool IsFixed,
-                                  int &ArgGPRsLeft) const;
+  ABIArgInfo classifyArgumentType(QualType Ty, bool IsFixed, int &ArgGPRsLeft,
+                                  int &ArgFPRsLeft) const;
   ABIArgInfo classifyReturnType(QualType RetTy) const;
 
   Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
                     QualType Ty) const override;
 
   ABIArgInfo extendType(QualType Ty) const;
+
+  bool detectFPCCEligibleStruct(QualType Ty, llvm::Type *&Field1Ty, CharUnits &Field1Off,
+                                llvm::Type *&Field2Ty, CharUnits &Field2Off,
+                                int &NeededArgGPRs, int &NeededArgFPRs) const;
+  ABIArgInfo coerceAndExpandFPCCEligibleStruct(llvm::Type *Field1Ty,
+                                               CharUnits Field1Off,
+                                               llvm::Type *Field2Ty,
+                                               CharUnits Field2Off) const;
 };
 } // end anonymous namespace
 
@@ -9228,18 +9247,214 @@ void RISCVABIInfo::computeInfo(CGFunctionInfo &FI) const {
   // different for variadic arguments, we must also track whether we are
   // examining a vararg or not.
   int ArgGPRsLeft = IsRetIndirect ? NumArgGPRs - 1 : NumArgGPRs;
+  int ArgFPRsLeft = FLen ? NumArgFPRs : 0;
   int NumFixedArgs = FI.getNumRequiredArgs();
 
   int ArgNum = 0;
   for (auto &ArgInfo : FI.arguments()) {
     bool IsFixed = ArgNum < NumFixedArgs;
-    ArgInfo.info = classifyArgumentType(ArgInfo.type, IsFixed, ArgGPRsLeft);
+    ArgInfo.info =
+        classifyArgumentType(ArgInfo.type, IsFixed, ArgGPRsLeft, ArgFPRsLeft);
     ArgNum++;
   }
 }
 
+// Returns true if the struct is a potential candidate for the floating point
+// calling convention. If this function returns true, the caller is
+// responsible for checking that if there is only a single field then that
+// field is a float.
+bool RISCVABIInfo::detectFPCCEligibleStructHelper(QualType Ty, CharUnits CurOff,
+                                                  llvm::Type *&Field1Ty,
+                                                  CharUnits &Field1Off,
+                                                  llvm::Type *&Field2Ty,
+                                                  CharUnits &Field2Off) const {
+  bool IsInt = Ty->isIntegralOrEnumerationType();
+  bool IsFloat = Ty->isRealFloatingType();
+
+  if (IsInt || IsFloat) {
+    uint64_t Size = getContext().getTypeSize(Ty);
+    if (IsInt && Size > XLen)
+      return false;
+    // Can't be eligible if larger than the FP registers. Half precision isn't
+    // currently supported on RISC-V and the ABI hasn't been confirmed, so
+    // default to the integer ABI in that case.
+    if (IsFloat && (Size > FLen || Size < 32))
+      return false;
+    // Can't be eligible if an integer type was already found (int+int pairs
+    // are not eligible).
+    if (IsInt && Field1Ty && Field1Ty->isIntegerTy())
+      return false;
+    if (!Field1Ty) {
+      Field1Ty = CGT.ConvertType(Ty);
+      Field1Off = CurOff;
+      return true;
+    }
+    if (!Field2Ty) {
+      Field2Ty = CGT.ConvertType(Ty);
+      Field2Off = CurOff;
+      return true;
+    }
+    return false;
+  }
+
+  if (auto CTy = Ty->getAs<ComplexType>()) {
+    if (Field1Ty)
+      return false;
+    QualType EltTy = CTy->getElementType();
+    if (getContext().getTypeSize(EltTy) > FLen)
+      return false;
+    Field1Ty = CGT.ConvertType(EltTy);
+    Field1Off = CurOff;
+    assert(CurOff.isZero() && "Unexpected offset for first field");
+    Field2Ty = Field1Ty;
+    Field2Off = Field1Off + getContext().getTypeSizeInChars(EltTy);
+    return true;
+  }
+
+  if (const ConstantArrayType *ATy = getContext().getAsConstantArrayType(Ty)) {
+    uint64_t ArraySize = ATy->getSize().getZExtValue();
+    QualType EltTy = ATy->getElementType();
+    CharUnits EltSize = getContext().getTypeSizeInChars(EltTy);
+    for (uint64_t i = 0; i < ArraySize; ++i) {
+      bool Ret = detectFPCCEligibleStructHelper(EltTy, CurOff, Field1Ty, Field1Off,
+                                                Field2Ty, Field2Off);
+      if (!Ret)
+        return false;
+      CurOff += EltSize;
+    }
+    return true;
+  }
+
+  if (const auto *RTy = Ty->getAs<RecordType>()) {
+    // Structures with either a non-trivial destructor or a non-trivial
+    // copy constructor are not eligible for the FP calling convention.
+    if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, CGT.getCXXABI()))
+      return false;
+    if (isEmptyRecord(getContext(), Ty, true))
+      return true;
+    const RecordDecl *RD = RTy->getDecl();
+    // Unions aren't eligible unless they're empty (which is caught above).
+    if (RD->isUnion())
+      return false;
+    int ZeroWidthBitFieldCount = 0;
+    for (const FieldDecl *FD : RD->fields()) {
+      const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
+      uint64_t FieldOffInBits = Layout.getFieldOffset(FD->getFieldIndex());
+      QualType QTy = FD->getType();
+      if (FD->isBitField()) {
+        unsigned BitWidth = FD->getBitWidthValue(getContext());
+        // Allow a bitfield with a type greater than XLen as long as the
+        // bitwidth is XLen or less.
+        if (getContext().getTypeSize(QTy) > XLen && BitWidth <= XLen)
+          QTy = getContext().getIntTypeForBitwidth(XLen, false);
+        if (BitWidth == 0) {
+          ZeroWidthBitFieldCount++;
+          continue;
+        }
+      }
+
+      bool Ret = detectFPCCEligibleStructHelper(
+          QTy, CurOff + getContext().toCharUnitsFromBits(FieldOffInBits),
+          Field1Ty, Field1Off, Field2Ty, Field2Off);
+      if (!Ret)
+        return false;
+
+      // As a quirk of the ABI, zero-width bitfields aren't ignored for fp+fp
+      // or int+fp structs, but are ignored for a struct with an fp field and
+      // any number of zero-width bitfields.
+      if (Field2Ty && ZeroWidthBitFieldCount > 0)
+        return false;
+    }
+    return Field1Ty != nullptr;
+  }
+
+  return false;
+}
+
+// Determine if a struct is eligible for passing according to the floating
+// point calling convention (i.e., when flattened it contains a single fp
+// value, fp+fp, or int+fp of appropriate size). If so, NeededArgFPRs and
+// NeededArgGPRs are incremented appropriately.
+bool RISCVABIInfo::detectFPCCEligibleStruct(QualType Ty, llvm::Type *&Field1Ty,
+                                            CharUnits &Field1Off,
+                                            llvm::Type *&Field2Ty,
+                                            CharUnits &Field2Off,
+                                            int &NeededArgGPRs,
+                                            int &NeededArgFPRs) const {
+  Field1Ty = nullptr;
+  Field2Ty = nullptr;
+  NeededArgGPRs = 0;
+  NeededArgFPRs = 0;
+  bool IsCandidate = detectFPCCEligibleStructHelper(
+      Ty, CharUnits::Zero(), Field1Ty, Field1Off, Field2Ty, Field2Off);
+  // Not really a candidate if we have a single int but no float.
+  if (Field1Ty && !Field2Ty && !Field1Ty->isFloatingPointTy())
+    return IsCandidate = false;
+  if (!IsCandidate)
+    return false;
+  if (Field1Ty && Field1Ty->isFloatingPointTy())
+    NeededArgFPRs++;
+  else if (Field1Ty)
+    NeededArgGPRs++;
+  if (Field2Ty && Field2Ty->isFloatingPointTy())
+    NeededArgFPRs++;
+  else if (Field2Ty)
+    NeededArgGPRs++;
+  return IsCandidate;
+}
+
+// Call getCoerceAndExpand for the two-element flattened struct described by
+// Field1Ty, Field1Off, Field2Ty, Field2Off. This method will create an appropriate
+// coerceToType and unpaddedCoerceToType.
+ABIArgInfo RISCVABIInfo::coerceAndExpandFPCCEligibleStruct(
+    llvm::Type *Field1Ty, CharUnits Field1Off, llvm::Type *Field2Ty, CharUnits Field2Off) const {
+  SmallVector<llvm::Type *, 3> CoerceElts;
+  SmallVector<llvm::Type *, 2> UnpaddedCoerceElts;
+  if (!Field1Off.isZero())
+    CoerceElts.push_back(llvm::ArrayType::get(
+        llvm::Type::getInt8Ty(getVMContext()), Field1Off.getQuantity()));
+
+  CoerceElts.push_back(Field1Ty);
+  UnpaddedCoerceElts.push_back(Field1Ty);
+
+  if (!Field2Ty) {
+    return ABIArgInfo::getCoerceAndExpand(
+        llvm::StructType::get(getVMContext(), CoerceElts, !Field1Off.isZero()),
+        UnpaddedCoerceElts[0]);
+  }
+
+  CharUnits Field2Align =
+      CharUnits::fromQuantity(getDataLayout().getABITypeAlignment(Field2Ty));
+  CharUnits Field1Size =
+      CharUnits::fromQuantity(getDataLayout().getTypeStoreSize(Field1Ty));
+  CharUnits Field2OffNoPadNoPack = Field1Size.alignTo(Field2Align);
+
+  CharUnits Padding = CharUnits::Zero();
+  if (Field2Off > Field2OffNoPadNoPack)
+    Padding = Field2Off - Field2OffNoPadNoPack;
+  else if (Field2Off != Field2Align && Field2Off > Field1Size)
+    Padding = Field2Off - Field1Size;
+
+  bool IsPacked = !Field2Off.isMultipleOf(Field2Align);
+
+  if (!Padding.isZero())
+    CoerceElts.push_back(llvm::ArrayType::get(
+        llvm::Type::getInt8Ty(getVMContext()), Padding.getQuantity()));
+
+  CoerceElts.push_back(Field2Ty);
+  UnpaddedCoerceElts.push_back(Field2Ty);
+
+  auto CoerceToType =
+      llvm::StructType::get(getVMContext(), CoerceElts, IsPacked);
+  auto UnpaddedCoerceToType =
+      llvm::StructType::get(getVMContext(), UnpaddedCoerceElts, IsPacked);
+
+  return ABIArgInfo::getCoerceAndExpand(CoerceToType, UnpaddedCoerceToType);
+}
+
 ABIArgInfo RISCVABIInfo::classifyArgumentType(QualType Ty, bool IsFixed,
-                                              int &ArgGPRsLeft) const {
+                                              int &ArgGPRsLeft,
+                                              int &ArgFPRsLeft) const {
   assert(ArgGPRsLeft <= NumArgGPRs && "Arg GPR tracking underflow");
   Ty = useFirstFieldIfTransparentUnion(Ty);
 
@@ -9257,6 +9472,40 @@ ABIArgInfo RISCVABIInfo::classifyArgumentType(QualType Ty, bool IsFixed,
     return ABIArgInfo::getIgnore();
 
   uint64_t Size = getContext().getTypeSize(Ty);
+
+  // Pass floating point values via FPRs if possible.
+  if (IsFixed && Ty->isFloatingType() && FLen >= Size && ArgFPRsLeft) {
+    ArgFPRsLeft--;
+    return ABIArgInfo::getDirect();
+  }
+
+  // Complex types for the hard float ABI must be passed direct rather than
+  // using CoerceAndExpand.
+  if (IsFixed && Ty->isComplexType() && FLen && ArgFPRsLeft >= 2) {
+    QualType EltTy = Ty->getAs<ComplexType>()->getElementType();
+    if (getContext().getTypeSize(EltTy) <= FLen) {
+      ArgFPRsLeft -= 2;
+      return ABIArgInfo::getDirect();
+    }
+  }
+
+  if (IsFixed && FLen && Ty->isStructureOrClassType()) {
+    llvm::Type *Field1Ty = nullptr;
+    llvm::Type *Field2Ty = nullptr;
+    CharUnits Field1Off = CharUnits::Zero();
+    CharUnits Field2Off = CharUnits::Zero();
+    int NeededArgGPRs;
+    int NeededArgFPRs;
+    bool IsCandidate = detectFPCCEligibleStruct(
+        Ty, Field1Ty, Field1Off, Field2Ty, Field2Off, NeededArgGPRs, NeededArgFPRs);
+    if (IsCandidate && NeededArgGPRs <= ArgGPRsLeft &&
+        NeededArgFPRs <= ArgFPRsLeft) {
+      ArgGPRsLeft -= NeededArgGPRs;
+      ArgFPRsLeft -= NeededArgFPRs;
+      return coerceAndExpandFPCCEligibleStruct(Field1Ty, Field1Off, Field2Ty, Field2Off);
+    }
+  }
+
   uint64_t NeededAlign = getContext().getTypeAlign(Ty);
   bool MustUseStack = false;
   // Determine the number of GPRs needed to pass the current argument
@@ -9315,10 +9564,12 @@ ABIArgInfo RISCVABIInfo::classifyReturnType(QualType RetTy) const {
     return ABIArgInfo::getIgnore();
 
   int ArgGPRsLeft = 2;
+  int ArgFPRsLeft = FLen ? 2 : 0;
 
   // The rules for return and argument types are the same, so defer to
   // classifyArgumentType.
-  return classifyArgumentType(RetTy, /*IsFixed=*/true, ArgGPRsLeft);
+  return classifyArgumentType(RetTy, /*IsFixed=*/true, ArgGPRsLeft,
+                              ArgFPRsLeft);
 }
 
 Address RISCVABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
@@ -9353,8 +9604,9 @@ ABIArgInfo RISCVABIInfo::extendType(QualType Ty) const {
 namespace {
 class RISCVTargetCodeGenInfo : public TargetCodeGenInfo {
 public:
-  RISCVTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT, unsigned XLen)
-      : TargetCodeGenInfo(new RISCVABIInfo(CGT, XLen)) {}
+  RISCVTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT, unsigned XLen,
+                         unsigned FLen)
+      : TargetCodeGenInfo(new RISCVABIInfo(CGT, XLen, FLen)) {}
 
   void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
                            CodeGen::CodeGenModule &CGM) const override {
@@ -9493,9 +9745,16 @@ const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
     return SetCGInfo(new MSP430TargetCodeGenInfo(Types));
 
   case llvm::Triple::riscv32:
-    return SetCGInfo(new RISCVTargetCodeGenInfo(Types, 32));
-  case llvm::Triple::riscv64:
-    return SetCGInfo(new RISCVTargetCodeGenInfo(Types, 64));
+  case llvm::Triple::riscv64: {
+    StringRef ABIStr = getTarget().getABI();
+    unsigned XLen = getTarget().getPointerWidth(0);
+    unsigned ABIFLen = 0;
+    if (ABIStr.endswith("f"))
+      ABIFLen = 32;
+    else if (ABIStr.endswith("d"))
+      ABIFLen = 64;
+    return SetCGInfo(new RISCVTargetCodeGenInfo(Types, XLen, ABIFLen));
+  }
 
   case llvm::Triple::systemz: {
     bool HasVector = getTarget().getABI() == "vector";

test/CodeGen/riscv32-ilp32-ilp32f-abi.c

@@ -1,4 +1,6 @@
 // RUN: %clang_cc1 -triple riscv32 -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple riscv32 -target-feature +f -target-abi ilp32f -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
 
 // This file contains test cases that will have the same output for the ilp32
 // and ilp32f ABIs.
@@ -35,8 +37,8 @@ int f_scalar_stack_1(int32_t a, int64_t b, int32_t c, double d, long double e,
 // the presence of large return values that consume a register due to the need
 // to pass a pointer.
 
-// CHECK-LABEL: define void @f_scalar_stack_2(%struct.large* noalias sret %agg.result, i32 %a, i64 %b, i64 %c, fp128 %d, i8 zeroext %e, i8 %f, i8 %g)
-struct large f_scalar_stack_2(int32_t a, int64_t b, int64_t c, long double d,
+// CHECK-LABEL: define void @f_scalar_stack_2(%struct.large* noalias sret %agg.result, i32 %a, i64 %b, double %c, fp128 %d, i8 zeroext %e, i8 %f, i8 %g)
+struct large f_scalar_stack_2(int32_t a, int64_t b, double c, long double d,
                               uint8_t e, int8_t f, uint8_t g) {
   return (struct large){a, e, f, g};
 }

test/CodeGen/riscv32-ilp32-ilp32f-ilp32d-abi.c

@@ -1,6 +1,10 @@
 // RUN: %clang_cc1 -triple riscv32 -emit-llvm %s -o - | FileCheck %s
 // RUN: %clang_cc1 -triple riscv32 -emit-llvm -fforce-enable-int128 %s -o - \
 // RUN:   | FileCheck %s -check-prefixes=CHECK,CHECK-FORCEINT128
+// RUN: %clang_cc1 -triple riscv32 -target-feature +f -target-abi ilp32f -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+// RUN: %clang_cc1 -triple riscv32 -target-feature +d -target-abi ilp32d -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
 
 // This file contains test cases that will have the same output for the ilp32,
 // ilp32f, and ilp32d ABIs.

test/CodeGen/riscv32-ilp32d-abi.c

@@ -0,0 +1,282 @@
+// RUN: %clang_cc1 -triple riscv32 -target-feature +d -target-abi ilp32d -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+
+#include <stdint.h>
+
+// Verify that the tracking of used GPRs and FPRs works correctly by checking
+// that small integers are sign/zero extended when passed in registers.
+
+// Doubles are passed in FPRs, so argument 'i' will be passed zero-extended
+// because it will be passed in a GPR.
+
+// CHECK: define void @f_fpr_tracking(double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, i8 zeroext %i)
+void f_fpr_tracking(double a, double b, double c, double d, double e, double f,
+                    double g, double h, uint8_t i) {}
+
+// Check that fp, fp+fp, and int+fp structs are lowered correctly. These will
+// be passed in FPR, FPR+FPR, or GPR+FPR regs if sufficient registers are
+// available the widths are <= XLEN and FLEN, and should be expanded to
+// separate arguments in IR. They are passed by the same rules for returns,
+// but will be lowered to simple two-element structs if necessary (as LLVM IR
+// functions cannot return multiple values).
+
+// A struct containing just one floating-point real is passed as though it
+// were a standalone floating-point real.
+
+struct double_s { double f; };
+
+// CHECK: define void @f_double_s_arg(double)
+void f_double_s_arg(struct double_s a) {}
+
+// CHECK: define double @f_ret_double_s()
+struct double_s f_ret_double_s() {
+  return (struct double_s){1.0};
+}
+
+// A struct containing a double and any number of zero-width bitfields is
+// passed as though it were a standalone floating-point real.
+
+struct zbf_double_s { int : 0; double f; };
+struct zbf_double_zbf_s { int : 0; double f; int : 0; };
+
+// CHECK: define void @f_zbf_double_s_arg(double)
+void f_zbf_double_s_arg(struct zbf_double_s a) {}
+
+// CHECK: define double @f_ret_zbf_double_s()
+struct zbf_double_s f_ret_zbf_double_s() {
+  return (struct zbf_double_s){1.0};
+}
+
+// CHECK: define void @f_zbf_double_zbf_s_arg(double)
+void f_zbf_double_zbf_s_arg(struct zbf_double_zbf_s a) {}
+
+// CHECK: define double @f_ret_zbf_double_zbf_s()
+struct zbf_double_zbf_s f_ret_zbf_double_zbf_s() {
+  return (struct zbf_double_zbf_s){1.0};
+}
+
+// Check that structs containing two floating point values (FLEN <= width) are
+// expanded provided sufficient FPRs are available.
+
+struct double_double_s { double f; double g; };
+struct double_float_s { double f; float g; };
+
+// CHECK: define void @f_double_double_s_arg(double, double)
+void f_double_double_s_arg(struct double_double_s a) {}
+
+// CHECK: define { double, double } @f_ret_double_double_s()
+struct double_double_s f_ret_double_double_s() {
+  return (struct double_double_s){1.0, 2.0};
+}
+
+// CHECK: define void @f_double_float_s_arg(double, float)
+void f_double_float_s_arg(struct double_float_s a) {}
+
+// CHECK: define { double, float } @f_ret_double_float_s()
+struct double_float_s f_ret_double_float_s() {
+  return (struct double_float_s){1.0, 2.0};
+}
+
+// CHECK: define void @f_double_double_s_arg_insufficient_fprs(float %a, double %b, double %c, double %d, double %e, double %f, double %g, %struct.double_double_s* %h)
+void f_double_double_s_arg_insufficient_fprs(float a, double b, double c, double d,
+    double e, double f, double g, struct double_double_s h) {}
+
+// Check that structs containing int+double values are expanded, provided
+// sufficient FPRs and GPRs are available. The integer components are neither
+// sign or zero-extended.
+
+struct double_int8_s { double f; int8_t i; };
+struct double_uint8_s { double f; uint8_t i; };
+struct double_int32_s { double f; int32_t i; };
+struct double_int64_s { double f; int64_t i; };
+struct double_int64bf_s { double f; int64_t i : 32; };
+struct double_int8_zbf_s { double f; int8_t i; int : 0; };
+
+// CHECK: define void @f_double_int8_s_arg(double, i8)
+void f_double_int8_s_arg(struct double_int8_s a) {}
+
+// CHECK: define { double, i8 } @f_ret_double_int8_s()
+struct double_int8_s f_ret_double_int8_s() {
+  return (struct double_int8_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_uint8_s_arg(double, i8)
+void f_double_uint8_s_arg(struct double_uint8_s a) {}
+
+// CHECK: define { double, i8 } @f_ret_double_uint8_s()
+struct double_uint8_s f_ret_double_uint8_s() {
+  return (struct double_uint8_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_int32_s_arg(double, i32)
+void f_double_int32_s_arg(struct double_int32_s a) {}
+
+// CHECK: define { double, i32 } @f_ret_double_int32_s()
+struct double_int32_s f_ret_double_int32_s() {
+  return (struct double_int32_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_int64_s_arg(%struct.double_int64_s* %a)
+void f_double_int64_s_arg(struct double_int64_s a) {}
+
+// CHECK: define void @f_ret_double_int64_s(%struct.double_int64_s* noalias sret %agg.result)
+struct double_int64_s f_ret_double_int64_s() {
+  return (struct double_int64_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_int64bf_s_arg(double, i32)
+void f_double_int64bf_s_arg(struct double_int64bf_s a) {}
+
+// CHECK: define { double, i32 } @f_ret_double_int64bf_s()
+struct double_int64bf_s f_ret_double_int64bf_s() {
+  return (struct double_int64bf_s){1.0, 2};
+}
+
+// The zero-width bitfield means the struct can't be passed according to the
+// floating point calling convention.
+
+// CHECK: define void @f_double_int8_zbf_s(double, i8)
+void f_double_int8_zbf_s(struct double_int8_zbf_s a) {}
+
+// CHECK: define { double, i8 } @f_ret_double_int8_zbf_s()
+struct double_int8_zbf_s f_ret_double_int8_zbf_s() {
+  return (struct double_int8_zbf_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_int8_s_arg_insufficient_gprs(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e, i32 %f, i32 %g, i32 %h, %struct.double_int8_s* %i)
+void f_double_int8_s_arg_insufficient_gprs(int a, int b, int c, int d, int e,
+                                          int f, int g, int h, struct double_int8_s i) {}
+
+// CHECK: define void @f_struct_double_int8_insufficient_fprs(float %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, %struct.double_int8_s* %i)
+void f_struct_double_int8_insufficient_fprs(float a, double b, double c, double d,
+                                           double e, double f, double g, double h, struct double_int8_s i) {}
+
+// Complex floating-point values or structs containing a single complex
+// floating-point value should be passed as if it were an fp+fp struct.
+
+// CHECK: define void @f_doublecomplex(double %a.coerce0, double %a.coerce1)
+void f_doublecomplex(double __complex__ a) {}
+
+// CHECK: define { double, double } @f_ret_doublecomplex()
+double __complex__ f_ret_doublecomplex() {
+  return 1.0;
+}
+
+struct doublecomplex_s { double __complex__ c; };
+
+// CHECK: define void @f_doublecomplex_s_arg(double, double)
+void f_doublecomplex_s_arg(struct doublecomplex_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublecomplex_s()
+struct doublecomplex_s f_ret_doublecomplex_s() {
+  return (struct doublecomplex_s){1.0};
+}
+
+// Test single or two-element structs that need flattening. e.g. those
+// containing nested structs, doubles in small arrays, zero-length structs etc.
+
+struct doublearr1_s { double a[1]; };
+
+// CHECK: define void @f_doublearr1_s_arg(double)
+void f_doublearr1_s_arg(struct doublearr1_s a) {}
+
+// CHECK: define double @f_ret_doublearr1_s()
+struct doublearr1_s f_ret_doublearr1_s() {
+  return (struct doublearr1_s){{1.0}};
+}
+
+struct doublearr2_s { double a[2]; };
+
+// CHECK: define void @f_doublearr2_s_arg(double, double)
+void f_doublearr2_s_arg(struct doublearr2_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_s()
+struct doublearr2_s f_ret_doublearr2_s() {
+  return (struct doublearr2_s){{1.0, 2.0}};
+}
+
+struct doublearr2_tricky1_s { struct { double f[1]; } g[2]; };
+
+// CHECK: define void @f_doublearr2_tricky1_s_arg(double, double)
+void f_doublearr2_tricky1_s_arg(struct doublearr2_tricky1_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky1_s()
+struct doublearr2_tricky1_s f_ret_doublearr2_tricky1_s() {
+  return (struct doublearr2_tricky1_s){{{{1.0}}, {{2.0}}}};
+}
+
+struct doublearr2_tricky2_s { struct {}; struct { double f[1]; } g[2]; };
+
+// CHECK: define void @f_doublearr2_tricky2_s_arg(double, double)
+void f_doublearr2_tricky2_s_arg(struct doublearr2_tricky2_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky2_s()
+struct doublearr2_tricky2_s f_ret_doublearr2_tricky2_s() {
+  return (struct doublearr2_tricky2_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct doublearr2_tricky3_s { union {}; struct { double f[1]; } g[2]; };
+
+// CHECK: define void @f_doublearr2_tricky3_s_arg(double, double)
+void f_doublearr2_tricky3_s_arg(struct doublearr2_tricky3_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky3_s()
+struct doublearr2_tricky3_s f_ret_doublearr2_tricky3_s() {
+  return (struct doublearr2_tricky3_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct doublearr2_tricky4_s { union {}; struct { struct {}; double f[1]; } g[2]; };
+
+// CHECK: define void @f_doublearr2_tricky4_s_arg(double, double)
+void f_doublearr2_tricky4_s_arg(struct doublearr2_tricky4_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky4_s()
+struct doublearr2_tricky4_s f_ret_doublearr2_tricky4_s() {
+  return (struct doublearr2_tricky4_s){{}, {{{}, {1.0}}, {{}, {2.0}}}};
+}
+
+// Test structs that should be passed according to the normal integer calling
+// convention.
+
+struct int_double_int_s { int a; double b; int c; };
+
+// CHECK: define void @f_int_double_int_s_arg(%struct.int_double_int_s* %a)
+void f_int_double_int_s_arg(struct int_double_int_s a) {}
+
+// CHECK: define void @f_ret_int_double_int_s(%struct.int_double_int_s* noalias sret %agg.result)
+struct int_double_int_s f_ret_int_double_int_s() {
+  return (struct int_double_int_s){1, 2.0, 3};
+}
+
+struct int64_double_s { int64_t a; double b; };
+
+// CHECK: define void @f_int64_double_s_arg(%struct.int64_double_s* %a)
+void f_int64_double_s_arg(struct int64_double_s a) {}
+
+// CHECK: define void @f_ret_int64_double_s(%struct.int64_double_s* noalias sret %agg.result)
+struct int64_double_s f_ret_int64_double_s() {
+  return (struct int64_double_s){1, 2.0};
+}
+
+struct char_char_double_s { char a; char b; double c; };
+
+// CHECK-LABEL: define void @f_char_char_double_s_arg(%struct.char_char_double_s* %a)
+void f_char_char_double_s_arg(struct char_char_double_s a) {}
+
+// CHECK: define void @f_ret_char_char_double_s(%struct.char_char_double_s* noalias sret %agg.result)
+struct char_char_double_s f_ret_char_char_double_s() {
+  return (struct char_char_double_s){1, 2, 3.0};
+}
+
+// Unions are always passed according to the integer calling convention, even
+// if they can only contain a double.
+
+union double_u { double a; };
+
+// CHECK: define void @f_double_u_arg(i64 %a.coerce)
+void f_double_u_arg(union double_u a) {}
+
+// CHECK: define i64 @f_ret_double_u()
+union double_u f_ret_double_u() {
+  return (union double_u){1.0};
+}

test/CodeGen/riscv32-ilp32f-abi.c

@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -triple riscv32 -target-feature +f -target-abi ilp32f -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+
+#include <stdint.h>
+
+// Doubles are still passed in GPRs, so the 'e' argument will be anyext as
+// GPRs are exhausted.
+
+// CHECK: define void @f_fpr_tracking(double %a, double %b, double %c, double %d, i8 %e)
+void f_fpr_tracking(double a, double b, double c, double d, int8_t e) {}
+
+// Lowering for doubles is unnmodified, as 64 > FLEN.
+
+struct double_s { double d; };
+
+// CHECK: define void @f_double_s_arg(i64 %a.coerce)
+void f_double_s_arg(struct double_s a) {}
+
+// CHECK: define i64 @f_ret_double_s()
+struct double_s f_ret_double_s() {
+  return (struct double_s){1.0};
+}
+
+struct double_double_s { double d; double e; };
+
+// CHECK: define void @f_double_double_s_arg(%struct.double_double_s* %a)
+void f_double_double_s_arg(struct double_double_s a) {}
+
+// CHECK: define void @f_ret_double_double_s(%struct.double_double_s* noalias sret %agg.result)
+struct double_double_s f_ret_double_double_s() {
+  return (struct double_double_s){1.0, 2.0};
+}
+
+struct double_int8_s { double d; int64_t i; };
+
+struct int_double_s { int a; double b; };
+
+// CHECK: define void @f_int_double_s_arg(%struct.int_double_s* %a)
+void f_int_double_s_arg(struct int_double_s a) {}
+
+// CHECK: define void @f_ret_int_double_s(%struct.int_double_s* noalias sret %agg.result)
+struct int_double_s f_ret_int_double_s() {
+  return (struct int_double_s){1, 2.0};
+}
+

test/CodeGen/riscv32-ilp32f-ilp32d-abi.c

@@ -0,0 +1,275 @@
+// RUN: %clang_cc1 -triple riscv32 -target-feature +f -target-abi ilp32f -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+// RUN: %clang_cc1 -triple riscv32 -target-feature +d -target-abi ilp32d -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+
+#include <stdint.h>
+
+// Verify that the tracking of used GPRs and FPRs works correctly by checking
+// that small integers are sign/zero extended when passed in registers.
+
+// Floats are passed in FPRs, so argument 'i' will be passed zero-extended 
+// because it will be passed in a GPR.
+
+// CHECK: define void @f_fpr_tracking(float %a, float %b, float %c, float %d, float %e, float %f, float %g, float %h, i8 zeroext %i)
+void f_fpr_tracking(float a, float b, float c, float d, float e, float f,
+                    float g, float h, uint8_t i) {}
+
+// Check that fp, fp+fp, and int+fp structs are lowered correctly. These will 
+// be passed in FPR, FPR+FPR, or GPR+FPR regs if sufficient registers are 
+// available the widths are <= XLEN and FLEN, and should be expanded to
+// separate arguments in IR. They are passed by the same rules for returns,
+// but will be lowered to simple two-element structs if necessary (as LLVM IR
+// functions cannot return multiple values).
+
+// A struct containing just one floating-point real is passed as though it 
+// were a standalone floating-point real.
+
+struct float_s { float f; };
+
+// CHECK: define void @f_float_s_arg(float)
+void f_float_s_arg(struct float_s a) {}
+
+// CHECK: define float @f_ret_float_s()
+struct float_s f_ret_float_s() {
+  return (struct float_s){1.0};
+}
+
+// A struct containing a float and any number of zero-width bitfields is
+// passed as though it were a standalone floating-point real.
+
+struct zbf_float_s { int : 0; float f; };
+struct zbf_float_zbf_s { int : 0; float f; int : 0; };
+
+// CHECK: define void @f_zbf_float_s_arg(float)
+void f_zbf_float_s_arg(struct zbf_float_s a) {}
+
+// CHECK: define float @f_ret_zbf_float_s()
+struct zbf_float_s f_ret_zbf_float_s() {
+  return (struct zbf_float_s){1.0};
+}
+
+// CHECK: define void @f_zbf_float_zbf_s_arg(float)
+void f_zbf_float_zbf_s_arg(struct zbf_float_zbf_s a) {}
+
+// CHECK: define float @f_ret_zbf_float_zbf_s()
+struct zbf_float_zbf_s f_ret_zbf_float_zbf_s() {
+  return (struct zbf_float_zbf_s){1.0};
+}
+
+// Check that structs containing two float values (FLEN <= width) are expanded
+// provided sufficient FPRs are available.
+
+struct float_float_s { float f; float g; };
+
+// CHECK: define void @f_float_float_s_arg(float, float)
+void f_float_float_s_arg(struct float_float_s a) {}
+
+// CHECK: define { float, float } @f_ret_float_float_s()
+struct float_float_s f_ret_float_float_s() {
+  return (struct float_float_s){1.0, 2.0};
+}
+
+// CHECK: define void @f_float_float_s_arg_insufficient_fprs(float %a, float %b, float %c, float %d, float %e, float %f, float %g, [2 x i32] %h.coerce)
+void f_float_float_s_arg_insufficient_fprs(float a, float b, float c, float d, 
+    float e, float f, float g, struct float_float_s h) {}
+
+// Check that structs containing int+float values are expanded, provided
+// sufficient FPRs and GPRs are available. The integer components are neither
+// sign or zero-extended.
+
+struct float_int8_s { float f; int8_t i; };
+struct float_uint8_s { float f; uint8_t i; };
+struct float_int32_s { float f; int32_t i; };
+struct float_int64_s { float f; int64_t i; };
+struct float_int64bf_s { float f; int64_t i : 32; };
+struct float_int8_zbf_s { float f; int8_t i; int : 0; };
+
+// CHECK: define void @f_float_int8_s_arg(float, i8)
+void f_float_int8_s_arg(struct float_int8_s a) {}
+
+// CHECK: define { float, i8 } @f_ret_float_int8_s()
+struct float_int8_s f_ret_float_int8_s() {
+  return (struct float_int8_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_uint8_s_arg(float, i8)
+void f_float_uint8_s_arg(struct float_uint8_s a) {}
+
+// CHECK: define { float, i8 } @f_ret_float_uint8_s()
+struct float_uint8_s f_ret_float_uint8_s() {
+  return (struct float_uint8_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_int32_s_arg(float, i32)
+void f_float_int32_s_arg(struct float_int32_s a) {}
+
+// CHECK: define { float, i32 } @f_ret_float_int32_s()
+struct float_int32_s f_ret_float_int32_s() {
+  return (struct float_int32_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_int64_s_arg(%struct.float_int64_s* %a)
+void f_float_int64_s_arg(struct float_int64_s a) {}
+
+// CHECK: define void @f_ret_float_int64_s(%struct.float_int64_s* noalias sret %agg.result)
+struct float_int64_s f_ret_float_int64_s() {
+  return (struct float_int64_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_int64bf_s_arg(float, i32)
+void f_float_int64bf_s_arg(struct float_int64bf_s a) {}
+
+// CHECK: define { float, i32 } @f_ret_float_int64bf_s()
+struct float_int64bf_s f_ret_float_int64bf_s() {
+  return (struct float_int64bf_s){1.0, 2};
+}
+
+// The zero-width bitfield means the struct can't be passed according to the
+// floating point calling convention.
+
+// CHECK: define void @f_float_int8_zbf_s(float, i8)
+void f_float_int8_zbf_s(struct float_int8_zbf_s a) {}
+
+// CHECK: define { float, i8 } @f_ret_float_int8_zbf_s()
+struct float_int8_zbf_s f_ret_float_int8_zbf_s() {
+  return (struct float_int8_zbf_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_int8_s_arg_insufficient_gprs(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e, i32 %f, i32 %g, i32 %h, [2 x i32] %i.coerce)
+void f_float_int8_s_arg_insufficient_gprs(int a, int b, int c, int d, int e,
+                                          int f, int g, int h, struct float_int8_s i) {}
+
+// CHECK: define void @f_struct_float_int8_insufficient_fprs(float %a, float %b, float %c, float %d, float %e, float %f, float %g, float %h, [2 x i32] %i.coerce)
+void f_struct_float_int8_insufficient_fprs(float a, float b, float c, float d,
+                                           float e, float f, float g, float h, struct float_int8_s i) {}
+
+// Complex floating-point values or structs containing a single complex 
+// floating-point value should be passed as if it were an fp+fp struct.
+
+// CHECK: define void @f_floatcomplex(float %a.coerce0, float %a.coerce1)
+void f_floatcomplex(float __complex__ a) {}
+
+// CHECK: define { float, float } @f_ret_floatcomplex()
+float __complex__ f_ret_floatcomplex() {
+  return 1.0;
+}
+
+struct floatcomplex_s { float __complex__ c; };
+
+// CHECK: define void @f_floatcomplex_s_arg(float, float)
+void f_floatcomplex_s_arg(struct floatcomplex_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatcomplex_s()
+struct floatcomplex_s f_ret_floatcomplex_s() {
+  return (struct floatcomplex_s){1.0};
+}
+
+// Test single or two-element structs that need flattening. e.g. those 
+// containing nested structs, floats in small arrays, zero-length structs etc.
+
+struct floatarr1_s { float a[1]; };
+
+// CHECK: define void @f_floatarr1_s_arg(float)
+void f_floatarr1_s_arg(struct floatarr1_s a) {}
+
+// CHECK: define float @f_ret_floatarr1_s()
+struct floatarr1_s f_ret_floatarr1_s() {
+  return (struct floatarr1_s){{1.0}};
+}
+
+struct floatarr2_s { float a[2]; };
+
+// CHECK: define void @f_floatarr2_s_arg(float, float)
+void f_floatarr2_s_arg(struct floatarr2_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_s()
+struct floatarr2_s f_ret_floatarr2_s() {
+  return (struct floatarr2_s){{1.0, 2.0}};
+}
+
+struct floatarr2_tricky1_s { struct { float f[1]; } g[2]; };
+
+// CHECK: define void @f_floatarr2_tricky1_s_arg(float, float)
+void f_floatarr2_tricky1_s_arg(struct floatarr2_tricky1_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky1_s()
+struct floatarr2_tricky1_s f_ret_floatarr2_tricky1_s() {
+  return (struct floatarr2_tricky1_s){{{{1.0}}, {{2.0}}}};
+}
+
+struct floatarr2_tricky2_s { struct {}; struct { float f[1]; } g[2]; };
+
+// CHECK: define void @f_floatarr2_tricky2_s_arg(float, float)
+void f_floatarr2_tricky2_s_arg(struct floatarr2_tricky2_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky2_s()
+struct floatarr2_tricky2_s f_ret_floatarr2_tricky2_s() {
+  return (struct floatarr2_tricky2_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct floatarr2_tricky3_s { union {}; struct { float f[1]; } g[2]; };
+
+// CHECK: define void @f_floatarr2_tricky3_s_arg(float, float)
+void f_floatarr2_tricky3_s_arg(struct floatarr2_tricky3_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky3_s()
+struct floatarr2_tricky3_s f_ret_floatarr2_tricky3_s() {
+  return (struct floatarr2_tricky3_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct floatarr2_tricky4_s { union {}; struct { struct {}; float f[1]; } g[2]; };
+
+// CHECK: define void @f_floatarr2_tricky4_s_arg(float, float)
+void f_floatarr2_tricky4_s_arg(struct floatarr2_tricky4_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky4_s()
+struct floatarr2_tricky4_s f_ret_floatarr2_tricky4_s() {
+  return (struct floatarr2_tricky4_s){{}, {{{}, {1.0}}, {{}, {2.0}}}};
+}
+
+// Test structs that should be passed according to the normal integer calling
+// convention.
+
+struct int_float_int_s { int a; float b; int c; };
+
+// CHECK: define void @f_int_float_int_s_arg(%struct.int_float_int_s* %a)
+void f_int_float_int_s_arg(struct int_float_int_s a) {}
+
+// CHECK: define void @f_ret_int_float_int_s(%struct.int_float_int_s* noalias sret %agg.result)
+struct int_float_int_s f_ret_int_float_int_s() {
+  return (struct int_float_int_s){1, 2.0, 3};
+}
+
+struct int64_float_s { int64_t a; float b; };
+
+// CHECK: define void @f_int64_float_s_arg(%struct.int64_float_s* %a)
+void f_int64_float_s_arg(struct int64_float_s a) {}
+
+// CHECK: define void @f_ret_int64_float_s(%struct.int64_float_s* noalias sret %agg.result)
+struct int64_float_s f_ret_int64_float_s() {
+  return (struct int64_float_s){1, 2.0};
+}
+
+struct char_char_float_s { char a; char b; float c; };
+
+// CHECK-LABEL: define void @f_char_char_float_s_arg([2 x i32] %a.coerce)
+void f_char_char_float_s_arg(struct char_char_float_s a) {}
+
+// CHECK: define [2 x i32] @f_ret_char_char_float_s()
+struct char_char_float_s f_ret_char_char_float_s() {
+  return (struct char_char_float_s){1, 2, 3.0};
+}
+
+// Unions are always passed according to the integer calling convention, even 
+// if they can only contain a float.
+
+union float_u { float a; };
+
+// CHECK: define void @f_float_u_arg(i32 %a.coerce)
+void f_float_u_arg(union float_u a) {}
+
+// CHECK: define i32 @f_ret_float_u()
+union float_u f_ret_float_u() {
+  return (union float_u){1.0};
+}

test/CodeGen/riscv64-lp64-lp64f-abi.c

@@ -1,4 +1,6 @@
 // RUN: %clang_cc1 -triple riscv64 -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple riscv64 -target-feature +f -target-abi lp64f -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
 
 // This file contains test cases that will have the same output for the lp64
 // and lp64f ABIs.

test/CodeGen/riscv64-lp64-lp64f-lp64d-abi.c

@@ -1,4 +1,8 @@
 // RUN: %clang_cc1 -triple riscv64 -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple riscv64 -target-feature +f -target-abi lp64f -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+// RUN: %clang_cc1 -triple riscv64 -target-feature +d -target-abi lp64d -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
 
 // This file contains test cases that will have the same output for the lp64,
 // lp64f, and lp64d ABIs.

test/CodeGen/riscv64-lp64d-abi.c

@@ -0,0 +1,272 @@
+// RUN: %clang_cc1 -triple riscv64 -target-feature +d -target-abi lp64d -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+
+#include <stdint.h>
+
+// Verify that the tracking of used GPRs and FPRs works correctly by checking
+// that small integers are sign/zero extended when passed in registers.
+
+// Doubles are passed in FPRs, so argument 'i' will be passed zero-extended
+// because it will be passed in a GPR.
+
+// CHECK: define void @f_fpr_tracking(double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, i8 zeroext %i)
+void f_fpr_tracking(double a, double b, double c, double d, double e, double f,
+                    double g, double h, uint8_t i) {}
+
+// Check that fp, fp+fp, and int+fp structs are lowered correctly. These will
+// be passed in FPR, FPR+FPR, or GPR+FPR regs if sufficient registers are
+// available the widths are <= XLEN and FLEN, and should be expanded to
+// separate arguments in IR. They are passed by the same rules for returns,
+// but will be lowered to simple two-element structs if necessary (as LLVM IR
+// functions cannot return multiple values).
+
+// A struct containing just one floating-point real is passed as though it
+// were a standalone floating-point real.
+
+struct double_s { double f; };
+
+// CHECK: define void @f_double_s_arg(double)
+void f_double_s_arg(struct double_s a) {}
+
+// CHECK: define double @f_ret_double_s()
+struct double_s f_ret_double_s() {
+  return (struct double_s){1.0};
+}
+
+// A struct containing a double and any number of zero-width bitfields is
+// passed as though it were a standalone floating-point real.
+
+struct zbf_double_s { int : 0; double f; };
+struct zbf_double_zbf_s { int : 0; double f; int : 0; };
+
+// CHECK: define void @f_zbf_double_s_arg(double)
+void f_zbf_double_s_arg(struct zbf_double_s a) {}
+
+// CHECK: define double @f_ret_zbf_double_s()
+struct zbf_double_s f_ret_zbf_double_s() {
+  return (struct zbf_double_s){1.0};
+}
+
+// CHECK: define void @f_zbf_double_zbf_s_arg(double)
+void f_zbf_double_zbf_s_arg(struct zbf_double_zbf_s a) {}
+
+// CHECK: define double @f_ret_zbf_double_zbf_s()
+struct zbf_double_zbf_s f_ret_zbf_double_zbf_s() {
+  return (struct zbf_double_zbf_s){1.0};
+}
+
+// Check that structs containing two floating point values (FLEN <= width) are
+// expanded provided sufficient FPRs are available.
+
+struct double_double_s { double f; double g; };
+struct double_float_s { double f; float g; };
+
+// CHECK: define void @f_double_double_s_arg(double, double)
+void f_double_double_s_arg(struct double_double_s a) {}
+
+// CHECK: define { double, double } @f_ret_double_double_s()
+struct double_double_s f_ret_double_double_s() {
+  return (struct double_double_s){1.0, 2.0};
+}
+
+// CHECK: define void @f_double_float_s_arg(double, float)
+void f_double_float_s_arg(struct double_float_s a) {}
+
+// CHECK: define { double, float } @f_ret_double_float_s()
+struct double_float_s f_ret_double_float_s() {
+  return (struct double_float_s){1.0, 2.0};
+}
+
+// CHECK: define void @f_double_double_s_arg_insufficient_fprs(float %a, double %b, double %c, double %d, double %e, double %f, double %g, [2 x i64] %h.coerce)
+void f_double_double_s_arg_insufficient_fprs(float a, double b, double c, double d,
+    double e, double f, double g, struct double_double_s h) {}
+
+// Check that structs containing int+double values are expanded, provided
+// sufficient FPRs and GPRs are available. The integer components are neither
+// sign or zero-extended.
+
+struct double_int8_s { double f; int8_t i; };
+struct double_uint8_s { double f; uint8_t i; };
+struct double_int32_s { double f; int32_t i; };
+struct double_int64_s { double f; int64_t i; };
+struct double_int128bf_s { double f; __int128_t i : 64; };
+struct double_int8_zbf_s { double f; int8_t i; int : 0; };
+
+// CHECK: define void @f_double_int8_s_arg(double, i8)
+void f_double_int8_s_arg(struct double_int8_s a) {}
+
+// CHECK: define { double, i8 } @f_ret_double_int8_s()
+struct double_int8_s f_ret_double_int8_s() {
+  return (struct double_int8_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_uint8_s_arg(double, i8)
+void f_double_uint8_s_arg(struct double_uint8_s a) {}
+
+// CHECK: define { double, i8 } @f_ret_double_uint8_s()
+struct double_uint8_s f_ret_double_uint8_s() {
+  return (struct double_uint8_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_int32_s_arg(double, i32)
+void f_double_int32_s_arg(struct double_int32_s a) {}
+
+// CHECK: define { double, i32 } @f_ret_double_int32_s()
+struct double_int32_s f_ret_double_int32_s() {
+  return (struct double_int32_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_int64_s_arg(double, i64)
+void f_double_int64_s_arg(struct double_int64_s a) {}
+
+// CHECK: define { double, i64 } @f_ret_double_int64_s()
+struct double_int64_s f_ret_double_int64_s() {
+  return (struct double_int64_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_int128bf_s_arg(double, i64)
+void f_double_int128bf_s_arg(struct double_int128bf_s a) {}
+
+// CHECK: define { double, i64 } @f_ret_double_int128bf_s()
+struct double_int128bf_s f_ret_double_int128bf_s() {
+  return (struct double_int128bf_s){1.0, 2};
+}
+
+// The zero-width bitfield means the struct can't be passed according to the
+// floating point calling convention.
+
+// CHECK: define void @f_double_int8_zbf_s(double, i8)
+void f_double_int8_zbf_s(struct double_int8_zbf_s a) {}
+
+// CHECK: define { double, i8 } @f_ret_double_int8_zbf_s()
+struct double_int8_zbf_s f_ret_double_int8_zbf_s() {
+  return (struct double_int8_zbf_s){1.0, 2};
+}
+
+// CHECK: define void @f_double_int8_s_arg_insufficient_gprs(i32 signext %a, i32 signext %b, i32 signext %c, i32 signext %d, i32 signext %e, i32 signext %f, i32 signext %g, i32 signext %h, [2 x i64] %i.coerce)
+void f_double_int8_s_arg_insufficient_gprs(int a, int b, int c, int d, int e,
+                                          int f, int g, int h, struct double_int8_s i) {}
+
+// CHECK: define void @f_struct_double_int8_insufficient_fprs(float %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, [2 x i64] %i.coerce)
+void f_struct_double_int8_insufficient_fprs(float a, double b, double c, double d,
+                                           double e, double f, double g, double h, struct double_int8_s i) {}
+
+// Complex floating-point values or structs containing a single complex
+// floating-point value should be passed as if it were an fp+fp struct.
+
+// CHECK: define void @f_doublecomplex(double %a.coerce0, double %a.coerce1)
+void f_doublecomplex(double __complex__ a) {}
+
+// CHECK: define { double, double } @f_ret_doublecomplex()
+double __complex__ f_ret_doublecomplex() {
+  return 1.0;
+}
+
+struct doublecomplex_s { double __complex__ c; };
+
+// CHECK: define void @f_doublecomplex_s_arg(double, double)
+void f_doublecomplex_s_arg(struct doublecomplex_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublecomplex_s()
+struct doublecomplex_s f_ret_doublecomplex_s() {
+  return (struct doublecomplex_s){1.0};
+}
+
+// Test single or two-element structs that need flattening. e.g. those
+// containing nested structs, doubles in small arrays, zero-length structs etc.
+
+struct doublearr1_s { double a[1]; };
+
+// CHECK: define void @f_doublearr1_s_arg(double)
+void f_doublearr1_s_arg(struct doublearr1_s a) {}
+
+// CHECK: define double @f_ret_doublearr1_s()
+struct doublearr1_s f_ret_doublearr1_s() {
+  return (struct doublearr1_s){{1.0}};
+}
+
+struct doublearr2_s { double a[2]; };
+
+// CHECK: define void @f_doublearr2_s_arg(double, double)
+void f_doublearr2_s_arg(struct doublearr2_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_s()
+struct doublearr2_s f_ret_doublearr2_s() {
+  return (struct doublearr2_s){{1.0, 2.0}};
+}
+
+struct doublearr2_tricky1_s { struct { double f[1]; } g[2]; };
+
+// CHECK: define void @f_doublearr2_tricky1_s_arg(double, double)
+void f_doublearr2_tricky1_s_arg(struct doublearr2_tricky1_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky1_s()
+struct doublearr2_tricky1_s f_ret_doublearr2_tricky1_s() {
+  return (struct doublearr2_tricky1_s){{{{1.0}}, {{2.0}}}};
+}
+
+struct doublearr2_tricky2_s { struct {}; struct { double f[1]; } g[2]; };
+
+// CHECK: define void @f_doublearr2_tricky2_s_arg(double, double)
+void f_doublearr2_tricky2_s_arg(struct doublearr2_tricky2_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky2_s()
+struct doublearr2_tricky2_s f_ret_doublearr2_tricky2_s() {
+  return (struct doublearr2_tricky2_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct doublearr2_tricky3_s { union {}; struct { double f[1]; } g[2]; };
+
+// CHECK: define void @f_doublearr2_tricky3_s_arg(double, double)
+void f_doublearr2_tricky3_s_arg(struct doublearr2_tricky3_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky3_s()
+struct doublearr2_tricky3_s f_ret_doublearr2_tricky3_s() {
+  return (struct doublearr2_tricky3_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct doublearr2_tricky4_s { union {}; struct { struct {}; double f[1]; } g[2]; };
+
+// CHECK: define void @f_doublearr2_tricky4_s_arg(double, double)
+void f_doublearr2_tricky4_s_arg(struct doublearr2_tricky4_s a) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky4_s()
+struct doublearr2_tricky4_s f_ret_doublearr2_tricky4_s() {
+  return (struct doublearr2_tricky4_s){{}, {{{}, {1.0}}, {{}, {2.0}}}};
+}
+
+// Test structs that should be passed according to the normal integer calling
+// convention.
+
+struct int_double_int_s { int a; double b; int c; };
+
+// CHECK: define void @f_int_double_int_s_arg(%struct.int_double_int_s* %a)
+void f_int_double_int_s_arg(struct int_double_int_s a) {}
+
+// CHECK: define void @f_ret_int_double_int_s(%struct.int_double_int_s* noalias sret %agg.result)
+struct int_double_int_s f_ret_int_double_int_s() {
+  return (struct int_double_int_s){1, 2.0, 3};
+}
+
+struct char_char_double_s { char a; char b; double c; };
+
+// CHECK-LABEL: define void @f_char_char_double_s_arg([2 x i64] %a.coerce)
+void f_char_char_double_s_arg(struct char_char_double_s a) {}
+
+// CHECK: define [2 x i64] @f_ret_char_char_double_s()
+struct char_char_double_s f_ret_char_char_double_s() {
+  return (struct char_char_double_s){1, 2, 3.0};
+}
+
+// Unions are always passed according to the integer calling convention, even
+// if they can only contain a double.
+
+union double_u { double a; };
+
+// CHECK: define void @f_double_u_arg(i64 %a.coerce)
+void f_double_u_arg(union double_u a) {}
+
+// CHECK: define i64 @f_ret_double_u()
+union double_u f_ret_double_u() {
+  return (union double_u){1.0};
+}

test/CodeGen/riscv64-lp64f-lp64d-abi.c

@@ -0,0 +1,265 @@
+// RUN: %clang_cc1 -triple riscv64 -target-feature +f -target-abi lp64f -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+// RUN: %clang_cc1 -triple riscv64 -target-feature +d -target-abi lp64d -emit-llvm %s -o - \
+// RUN:     | FileCheck %s
+
+#include <stdint.h>
+
+// Verify that the tracking of used GPRs and FPRs works correctly by checking
+// that small integers are sign/zero extended when passed in registers.
+
+// Floats are passed in FPRs, so argument 'i' will be passed zero-extended
+// because it will be passed in a GPR.
+
+// CHECK: define void @f_fpr_tracking(float %a, float %b, float %c, float %d, float %e, float %f, float %g, float %h, i8 zeroext %i)
+void f_fpr_tracking(float a, float b, float c, float d, float e, float f,
+                    float g, float h, uint8_t i) {}
+
+// Check that fp, fp+fp, and int+fp structs are lowered correctly. These will
+// be passed in FPR, FPR+FPR, or GPR+FPR regs if sufficient registers are
+// available the widths are <= XLEN and FLEN, and should be expanded to
+// separate arguments in IR. They are passed by the same rules for returns,
+// but will be lowered to simple two-element structs if necessary (as LLVM IR
+// functions cannot return multiple values).
+
+// A struct containing just one floating-point real is passed as though it
+// were a standalone floating-point real.
+
+struct float_s { float f; };
+
+// CHECK: define void @f_float_s_arg(float)
+void f_float_s_arg(struct float_s a) {}
+
+// CHECK: define float @f_ret_float_s()
+struct float_s f_ret_float_s() {
+  return (struct float_s){1.0};
+}
+
+// A struct containing a float and any number of zero-width bitfields is
+// passed as though it were a standalone floating-point real.
+
+struct zbf_float_s { int : 0; float f; };
+struct zbf_float_zbf_s { int : 0; float f; int : 0; };
+
+// CHECK: define void @f_zbf_float_s_arg(float)
+void f_zbf_float_s_arg(struct zbf_float_s a) {}
+
+// CHECK: define float @f_ret_zbf_float_s()
+struct zbf_float_s f_ret_zbf_float_s() {
+  return (struct zbf_float_s){1.0};
+}
+
+// CHECK: define void @f_zbf_float_zbf_s_arg(float)
+void f_zbf_float_zbf_s_arg(struct zbf_float_zbf_s a) {}
+
+// CHECK: define float @f_ret_zbf_float_zbf_s()
+struct zbf_float_zbf_s f_ret_zbf_float_zbf_s() {
+  return (struct zbf_float_zbf_s){1.0};
+}
+
+// Check that structs containing two float values (FLEN <= width) are expanded
+// provided sufficient FPRs are available.
+
+struct float_float_s { float f; float g; };
+
+// CHECK: define void @f_float_float_s_arg(float, float)
+void f_float_float_s_arg(struct float_float_s a) {}
+
+// CHECK: define { float, float } @f_ret_float_float_s()
+struct float_float_s f_ret_float_float_s() {
+  return (struct float_float_s){1.0, 2.0};
+}
+
+// CHECK: define void @f_float_float_s_arg_insufficient_fprs(float %a, float %b, float %c, float %d, float %e, float %f, float %g, i64 %h.coerce)
+void f_float_float_s_arg_insufficient_fprs(float a, float b, float c, float d,
+    float e, float f, float g, struct float_float_s h) {}
+
+// Check that structs containing int+float values are expanded, provided
+// sufficient FPRs and GPRs are available. The integer components are neither
+// sign or zero-extended.
+
+struct float_int8_s { float f; int8_t i; };
+struct float_uint8_s { float f; uint8_t i; };
+struct float_int32_s { float f; int32_t i; };
+struct float_int64_s { float f; int64_t i; };
+struct float_int128bf_s { float f; __int128_t i : 64; };
+struct float_int8_zbf_s { float f; int8_t i; int : 0; };
+
+// CHECK: define void @f_float_int8_s_arg(float, i8)
+void f_float_int8_s_arg(struct float_int8_s a) {}
+
+// CHECK: define { float, i8 } @f_ret_float_int8_s()
+struct float_int8_s f_ret_float_int8_s() {
+  return (struct float_int8_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_uint8_s_arg(float, i8)
+void f_float_uint8_s_arg(struct float_uint8_s a) {}
+
+// CHECK: define { float, i8 } @f_ret_float_uint8_s()
+struct float_uint8_s f_ret_float_uint8_s() {
+  return (struct float_uint8_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_int32_s_arg(float, i32)
+void f_float_int32_s_arg(struct float_int32_s a) {}
+
+// CHECK: define { float, i32 } @f_ret_float_int32_s()
+struct float_int32_s f_ret_float_int32_s() {
+  return (struct float_int32_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_int64_s_arg(float, i64)
+void f_float_int64_s_arg(struct float_int64_s a) {}
+
+// CHECK: define { float, i64 } @f_ret_float_int64_s()
+struct float_int64_s f_ret_float_int64_s() {
+  return (struct float_int64_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_int128bf_s_arg(float, i64)
+void f_float_int128bf_s_arg(struct float_int128bf_s a) {}
+
+// CHECK: define <{ float, i64 }> @f_ret_float_int128bf_s()
+struct float_int128bf_s f_ret_float_int128bf_s() {
+  return (struct float_int128bf_s){1.0, 2};
+}
+
+// The zero-width bitfield means the struct can't be passed according to the
+// floating point calling convention.
+
+// CHECK: define void @f_float_int8_zbf_s(float, i8)
+void f_float_int8_zbf_s(struct float_int8_zbf_s a) {}
+
+// CHECK: define { float, i8 } @f_ret_float_int8_zbf_s()
+struct float_int8_zbf_s f_ret_float_int8_zbf_s() {
+  return (struct float_int8_zbf_s){1.0, 2};
+}
+
+// CHECK: define void @f_float_int8_s_arg_insufficient_gprs(i32 signext %a, i32 signext %b, i32 signext %c, i32 signext %d, i32 signext %e, i32 signext %f, i32 signext %g, i32 signext %h, i64 %i.coerce)
+void f_float_int8_s_arg_insufficient_gprs(int a, int b, int c, int d, int e,
+                                          int f, int g, int h, struct float_int8_s i) {}
+
+// CHECK: define void @f_struct_float_int8_insufficient_fprs(float %a, float %b, float %c, float %d, float %e, float %f, float %g, float %h, i64 %i.coerce)
+void f_struct_float_int8_insufficient_fprs(float a, float b, float c, float d,
+                                           float e, float f, float g, float h, struct float_int8_s i) {}
+
+// Complex floating-point values or structs containing a single complex
+// floating-point value should be passed as if it were an fp+fp struct.
+
+// CHECK: define void @f_floatcomplex(float %a.coerce0, float %a.coerce1)
+void f_floatcomplex(float __complex__ a) {}
+
+// CHECK: define { float, float } @f_ret_floatcomplex()
+float __complex__ f_ret_floatcomplex() {
+  return 1.0;
+}
+
+struct floatcomplex_s { float __complex__ c; };
+
+// CHECK: define void @f_floatcomplex_s_arg(float, float)
+void f_floatcomplex_s_arg(struct floatcomplex_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatcomplex_s()
+struct floatcomplex_s f_ret_floatcomplex_s() {
+  return (struct floatcomplex_s){1.0};
+}
+
+// Test single or two-element structs that need flattening. e.g. those
+// containing nested structs, floats in small arrays, zero-length structs etc.
+
+struct floatarr1_s { float a[1]; };
+
+// CHECK: define void @f_floatarr1_s_arg(float)
+void f_floatarr1_s_arg(struct floatarr1_s a) {}
+
+// CHECK: define float @f_ret_floatarr1_s()
+struct floatarr1_s f_ret_floatarr1_s() {
+  return (struct floatarr1_s){{1.0}};
+}
+
+struct floatarr2_s { float a[2]; };
+
+// CHECK: define void @f_floatarr2_s_arg(float, float)
+void f_floatarr2_s_arg(struct floatarr2_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_s()
+struct floatarr2_s f_ret_floatarr2_s() {
+  return (struct floatarr2_s){{1.0, 2.0}};
+}
+
+struct floatarr2_tricky1_s { struct { float f[1]; } g[2]; };
+
+// CHECK: define void @f_floatarr2_tricky1_s_arg(float, float)
+void f_floatarr2_tricky1_s_arg(struct floatarr2_tricky1_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky1_s()
+struct floatarr2_tricky1_s f_ret_floatarr2_tricky1_s() {
+  return (struct floatarr2_tricky1_s){{{{1.0}}, {{2.0}}}};
+}
+
+struct floatarr2_tricky2_s { struct {}; struct { float f[1]; } g[2]; };
+
+// CHECK: define void @f_floatarr2_tricky2_s_arg(float, float)
+void f_floatarr2_tricky2_s_arg(struct floatarr2_tricky2_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky2_s()
+struct floatarr2_tricky2_s f_ret_floatarr2_tricky2_s() {
+  return (struct floatarr2_tricky2_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct floatarr2_tricky3_s { union {}; struct { float f[1]; } g[2]; };
+
+// CHECK: define void @f_floatarr2_tricky3_s_arg(float, float)
+void f_floatarr2_tricky3_s_arg(struct floatarr2_tricky3_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky3_s()
+struct floatarr2_tricky3_s f_ret_floatarr2_tricky3_s() {
+  return (struct floatarr2_tricky3_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct floatarr2_tricky4_s { union {}; struct { struct {}; float f[1]; } g[2]; };
+
+// CHECK: define void @f_floatarr2_tricky4_s_arg(float, float)
+void f_floatarr2_tricky4_s_arg(struct floatarr2_tricky4_s a) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky4_s()
+struct floatarr2_tricky4_s f_ret_floatarr2_tricky4_s() {
+  return (struct floatarr2_tricky4_s){{}, {{{}, {1.0}}, {{}, {2.0}}}};
+}
+
+// Test structs that should be passed according to the normal integer calling
+// convention.
+
+struct int_float_int_s { int a; float b; int c; };
+
+// CHECK: define void @f_int_float_int_s_arg([2 x i64] %a.coerce)
+void f_int_float_int_s_arg(struct int_float_int_s a) {}
+
+// CHECK: define [2 x i64] @f_ret_int_float_int_s()
+struct int_float_int_s f_ret_int_float_int_s() {
+  return (struct int_float_int_s){1, 2.0, 3};
+}
+
+struct char_char_float_s { char a; char b; float c; };
+
+// CHECK-LABEL: define void @f_char_char_float_s_arg(i64 %a.coerce)
+void f_char_char_float_s_arg(struct char_char_float_s a) {}
+
+// CHECK: define i64 @f_ret_char_char_float_s()
+struct char_char_float_s f_ret_char_char_float_s() {
+  return (struct char_char_float_s){1, 2, 3.0};
+}
+
+// Unions are always passed according to the integer calling convention, even
+// if they can only contain a float.
+
+union float_u { float a; };
+
+// CHECK: define void @f_float_u_arg(i64 %a.coerce)
+void f_float_u_arg(union float_u a) {}
+
+// CHECK: define i64 @f_ret_float_u()
+union float_u f_ret_float_u() {
+  return (union float_u){1.0};
+}

test/Preprocessor/riscv-target-features.c

@@ -47,3 +47,27 @@
 // RUN: %clang -target riscv64-unknown-linux-gnu -march=rv64ic -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-C-EXT %s
 // CHECK-C-EXT: __riscv_compressed 1
+
+// RUN: %clang -target riscv32-unknown-linux-gnu -march=rv32ifd -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-SOFT %s
+// RUN: %clang -target riscv64-unknown-linux-gnu -march=rv64ifd -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-SOFT %s
+// CHECK-SOFT: __riscv_float_abi_soft 1
+// CHECK-SOFT-NOT: __riscv_float_abi_single
+// CHECK-SOFT-NOT: __riscv_float_abi_double
+
+// RUN: %clang -target riscv32-unknown-linux-gnu -march=rv32ifd -mabi=ilp32f -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-SINGLE %s
+// RUN: %clang -target riscv64-unknown-linux-gnu -march=rv64ifd -mabi=lp64f -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-SINGLE %s
+// CHECK-SINGLE: __riscv_float_abi_single 1
+// CHECK-SINGLE-NOT: __riscv_float_abi_soft
+// CHECK-SINGLE-NOT: __riscv_float_abi_double
+
+// RUN: %clang -target riscv32-unknown-linux-gnu -march=rv32ifd -mabi=ilp32f -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-DOUBLE %s
+// RUN: %clang -target riscv64-unknown-linux-gnu -march=rv64ifd -mabi=lp64f -x c -E -dM %s \
+// RUN: -o - | FileCheck --check-prefix=CHECK-DOUBLE %s
+// CHECK-DOUBLE: __riscv_float_abi_double 1
+// CHECK-DOUBLE-NOT: __riscv_float_abi_soft
+// CHECK-DOUBLE-NOT: __riscv_float_abi_single