[PGO] Detect more structural changes with the stable hash

Lifting from Bob Wilson's notes: The hash value that we compute and
store in PGO profile data to detect out-of-date profiles does not
include enough information. This means that many significant changes to
the source will not cause compiler warnings about the profile being out
of date, and worse, we may continue to use the outdated profile data to
make bad optimization decisions.  There is some tension here because
some source changes won't affect PGO and we don't want to invalidate the
profile unnecessarily.

This patch adds a new hashing scheme which is more sensitive to loop
nesting, conditions, and out-of-order control flow. Here are examples
which show snippets which get the same hash under the current scheme,
and different hashes under the new scheme:

Loop Nesting Example
--------------------

  // Snippet 1
  while (foo()) {
    while (bar()) {}
  }

  // Snippet 2
  while (foo()) {}
  while (bar()) {}

Condition Example
-----------------

  // Snippet 1
  if (foo())
    bar();
  baz();

  // Snippet 2
  if (foo())
    bar();
  else
    baz();

Out-of-order Control Flow Example
---------------------------------

  // Snippet 1
  while (foo()) {
    if (bar()) {}
    baz();
  }

  // Snippet 2
  while (foo()) {
    if (bar())
      continue;
    baz();
  }

In each of these cases, it's useful to differentiate between the
snippets because swapping their profiles gives bad optimization hints.

The new hashing scheme considers some logical operators in an effort to
detect more changes in conditions. This isn't a perfect scheme. E.g, it
does not produce the same hash for these equivalent snippets:

  // Snippet 1
  bool c = !a || b;
  if (d && e) {}

  // Snippet 2
  bool f = d && e;
  bool c = !a || b;
  if (f) {}

This would require an expensive data flow analysis. Short of that, the
new hashing scheme looks reasonably complete, based on a scan over the
statements we place counters on.

Profiles which use the old version of the PGO hash remain valid and can
be used without issue (there are tests in tree which check this).

rdar://17068282

Differential Revision: https://reviews.llvm.org/D39446

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@318229 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CodeGenPGO.cpp

@@ -47,6 +47,15 @@ void CodeGenPGO::setFuncName(llvm::Function *Fn) {
   llvm::createPGOFuncNameMetadata(*Fn, FuncName);
 }
 
+/// The version of the PGO hash algorithm.
+enum PGOHashVersion : unsigned {
+  PGO_HASH_V1,
+  PGO_HASH_V2,
+
+  // Keep this set to the latest hash version.
+  PGO_HASH_LATEST = PGO_HASH_V2
+};
+
 namespace {
 /// \brief Stable hasher for PGO region counters.
 ///
@@ -61,6 +70,7 @@ namespace {
 class PGOHash {
   uint64_t Working;
   unsigned Count;
+  PGOHashVersion HashVersion;
   llvm::MD5 MD5;
 
   static const int NumBitsPerType = 6;
@@ -93,24 +103,53 @@ public:
     BinaryOperatorLAnd,
     BinaryOperatorLOr,
     BinaryConditionalOperator,
+    // The preceding values are available with PGO_HASH_V1.
+
+    EndOfScope,
+    IfThenBranch,
+    IfElseBranch,
+    GotoStmt,
+    IndirectGotoStmt,
+    BreakStmt,
+    ContinueStmt,
+    ReturnStmt,
+    ThrowExpr,
+    UnaryOperatorLNot,
+    BinaryOperatorLT,
+    BinaryOperatorGT,
+    BinaryOperatorLE,
+    BinaryOperatorGE,
+    BinaryOperatorEQ,
+    BinaryOperatorNE,
+    // The preceding values are available with PGO_HASH_V2.
 
     // Keep this last.  It's for the static assert that follows.
     LastHashType
   };
   static_assert(LastHashType <= TooBig, "Too many types in HashType");
 
-  // TODO: When this format changes, take in a version number here, and use the
-  // old hash calculation for file formats that used the old hash.
-  PGOHash() : Working(0), Count(0) {}
+  PGOHash(PGOHashVersion HashVersion)
+      : Working(0), Count(0), HashVersion(HashVersion), MD5() {}
   void combine(HashType Type);
   uint64_t finalize();
+  PGOHashVersion getHashVersion() const { return HashVersion; }
 };
 const int PGOHash::NumBitsPerType;
 const unsigned PGOHash::NumTypesPerWord;
 const unsigned PGOHash::TooBig;
 
+/// Get the PGO hash version used in the given indexed profile.
+static PGOHashVersion getPGOHashVersion(llvm::IndexedInstrProfReader *PGOReader,
+                                        CodeGenModule &CGM) {
+  if (PGOReader->getVersion() <= 4)
+    return PGO_HASH_V1;
+  return PGO_HASH_V2;
+}
+
 /// A RecursiveASTVisitor that fills a map of statements to PGO counters.
 struct MapRegionCounters : public RecursiveASTVisitor<MapRegionCounters> {
+  using Base = RecursiveASTVisitor<MapRegionCounters>;
+
   /// The next counter value to assign.
   unsigned NextCounter;
   /// The function hash.
@@ -118,8 +157,9 @@ struct MapRegionCounters : public RecursiveASTVisitor<MapRegionCounters> {
   /// The map of statements to counters.
   llvm::DenseMap<const Stmt *, unsigned> &CounterMap;
 
-  MapRegionCounters(llvm::DenseMap<const Stmt *, unsigned> &CounterMap)
-      : NextCounter(0), CounterMap(CounterMap) {}
+  MapRegionCounters(PGOHashVersion HashVersion,
+                    llvm::DenseMap<const Stmt *, unsigned> &CounterMap)
+      : NextCounter(0), Hash(HashVersion), CounterMap(CounterMap) {}
 
   // Blocks and lambdas are handled as separate functions, so we need not
   // traverse them in the parent context.
@@ -145,16 +185,66 @@ struct MapRegionCounters : public RecursiveASTVisitor<MapRegionCounters> {
     return true;
   }
 
-  bool VisitStmt(const Stmt *S) {
-    auto Type = getHashType(S);
-    if (Type == PGOHash::None)
-      return true;
+  /// If \p S gets a fresh counter, update the counter mappings. Return the
+  /// V1 hash of \p S.
+  PGOHash::HashType updateCounterMappings(Stmt *S) {
+    auto Type = getHashType(PGO_HASH_V1, S);
+    if (Type != PGOHash::None)
+      CounterMap[S] = NextCounter++;
+    return Type;
+  }
 
-    CounterMap[S] = NextCounter++;
-    Hash.combine(Type);
+  /// Include \p S in the function hash.
+  bool VisitStmt(Stmt *S) {
+    auto Type = updateCounterMappings(S);
+    if (Hash.getHashVersion() != PGO_HASH_V1)
+      Type = getHashType(Hash.getHashVersion(), S);
+    if (Type != PGOHash::None)
+      Hash.combine(Type);
     return true;
   }
-  PGOHash::HashType getHashType(const Stmt *S) {
+
+  bool TraverseIfStmt(IfStmt *If) {
+    // If we used the V1 hash, use the default traversal.
+    if (Hash.getHashVersion() == PGO_HASH_V1)
+      return Base::TraverseIfStmt(If);
+
+    // Otherwise, keep track of which branch we're in while traversing.
+    VisitStmt(If);
+    for (Stmt *CS : If->children()) {
+      if (!CS)
+        continue;
+      if (CS == If->getThen())
+        Hash.combine(PGOHash::IfThenBranch);
+      else if (CS == If->getElse())
+        Hash.combine(PGOHash::IfElseBranch);
+      TraverseStmt(CS);
+    }
+    Hash.combine(PGOHash::EndOfScope);
+    return true;
+  }
+
+// If the statement type \p N is nestable, and its nesting impacts profile
+// stability, define a custom traversal which tracks the end of the statement
+// in the hash (provided we're not using the V1 hash).
+#define DEFINE_NESTABLE_TRAVERSAL(N)                                           \
+  bool Traverse##N(N *S) {                                                     \
+    Base::Traverse##N(S);                                                      \
+    if (Hash.getHashVersion() != PGO_HASH_V1)                                  \
+      Hash.combine(PGOHash::EndOfScope);                                       \
+    return true;                                                               \
+  }
+
+  DEFINE_NESTABLE_TRAVERSAL(WhileStmt)
+  DEFINE_NESTABLE_TRAVERSAL(DoStmt)
+  DEFINE_NESTABLE_TRAVERSAL(ForStmt)
+  DEFINE_NESTABLE_TRAVERSAL(CXXForRangeStmt)
+  DEFINE_NESTABLE_TRAVERSAL(ObjCForCollectionStmt)
+  DEFINE_NESTABLE_TRAVERSAL(CXXTryStmt)
+  DEFINE_NESTABLE_TRAVERSAL(CXXCatchStmt)
+
+  /// Get version \p HashVersion of the PGO hash for \p S.
+  PGOHash::HashType getHashType(PGOHashVersion HashVersion, const Stmt *S) {
     switch (S->getStmtClass()) {
     default:
       break;
@@ -192,9 +282,53 @@ struct MapRegionCounters : public RecursiveASTVisitor<MapRegionCounters> {
         return PGOHash::BinaryOperatorLAnd;
       if (BO->getOpcode() == BO_LOr)
         return PGOHash::BinaryOperatorLOr;
+      if (HashVersion == PGO_HASH_V2) {
+        switch (BO->getOpcode()) {
+        default:
+          break;
+        case BO_LT:
+          return PGOHash::BinaryOperatorLT;
+        case BO_GT:
+          return PGOHash::BinaryOperatorGT;
+        case BO_LE:
+          return PGOHash::BinaryOperatorLE;
+        case BO_GE:
+          return PGOHash::BinaryOperatorGE;
+        case BO_EQ:
+          return PGOHash::BinaryOperatorEQ;
+        case BO_NE:
+          return PGOHash::BinaryOperatorNE;
+        }
+      }
       break;
     }
     }
+
+    if (HashVersion == PGO_HASH_V2) {
+      switch (S->getStmtClass()) {
+      default:
+        break;
+      case Stmt::GotoStmtClass:
+        return PGOHash::GotoStmt;
+      case Stmt::IndirectGotoStmtClass:
+        return PGOHash::IndirectGotoStmt;
+      case Stmt::BreakStmtClass:
+        return PGOHash::BreakStmt;
+      case Stmt::ContinueStmtClass:
+        return PGOHash::ContinueStmt;
+      case Stmt::ReturnStmtClass:
+        return PGOHash::ReturnStmt;
+      case Stmt::CXXThrowExprClass:
+        return PGOHash::ThrowExpr;
+      case Stmt::UnaryOperatorClass: {
+        const UnaryOperator *UO = cast<UnaryOperator>(S);
+        if (UO->getOpcode() == UO_LNot)
+          return PGOHash::UnaryOperatorLNot;
+        break;
+      }
+      }
+    }
+
     return PGOHash::None;
   }
 };
@@ -653,8 +787,14 @@ void CodeGenPGO::assignRegionCounters(GlobalDecl GD, llvm::Function *Fn) {
 }
 
 void CodeGenPGO::mapRegionCounters(const Decl *D) {
+  // Use the latest hash version when inserting instrumentation, but use the
+  // version in the indexed profile if we're reading PGO data.
+  PGOHashVersion HashVersion = PGO_HASH_LATEST;
+  if (auto *PGOReader = CGM.getPGOReader())
+    HashVersion = getPGOHashVersion(PGOReader, CGM);
+
   RegionCounterMap.reset(new llvm::DenseMap<const Stmt *, unsigned>);
-  MapRegionCounters Walker(*RegionCounterMap);
+  MapRegionCounters Walker(HashVersion, *RegionCounterMap);
   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
     Walker.TraverseDecl(const_cast<FunctionDecl *>(FD));
   else if (const ObjCMethodDecl *MD = dyn_cast_or_null<ObjCMethodDecl>(D))

test/Frontend/Inputs/optimization-remark-with-hotness.proftext

@@ -1,6 +1,6 @@
 foo
 # Func Hash:
-0
+24
 # Num Counters:
 1
 # Counter Values:
@@ -16,7 +16,7 @@ bar
 
 main
 # Func Hash:
-4
+1160280
 # Num Counters:
 2
 # Counter Values:

test/Profile/Inputs/c-captured.proftext

@@ -1,23 +1,23 @@
 c-captured.c:__captured_stmt
-10
+42129
 2
 1
 1
 
 c-captured.c:__captured_stmt.1
-266
+4752450705
 3
 1
 10
 1
 
 main
-0
+24
 1
 1
 
 debug_captured
-650
+11043906705
 3
 1
 1

test/Profile/Inputs/c-counter-overflows.proftext

@@ -1,5 +1,5 @@
 main
-285734896137
+10111551811706059223
 8
 1
 68719476720

test/Profile/Inputs/c-general.proftext

@@ -1,5 +1,5 @@
 simple_loops
-16515
+1245818015463121
 4
 1
 100
@@ -7,7 +7,7 @@ simple_loops
 75
 
 conditionals
-74917022372782735
+4190663230902537370
 11
 1
 100
@@ -22,7 +22,7 @@ conditionals
 100
 
 early_exits
-44128811889290
+8265526549255474475
 9
 1
 0
@@ -35,7 +35,7 @@ early_exits
 0
 
 jumps
-2016037664281362839
+15872630527555456493
 22
 1
 1
@@ -61,7 +61,7 @@ jumps
 9
 
 switches
-2745195701975551402
+11892326508727782373
 19
 1
 1
@@ -84,7 +84,7 @@ switches
 0
 
 big_switch
-10218718452081869619
+16933280399284440835
 17
 1
 32
@@ -105,7 +105,7 @@ big_switch
 2
 
 boolean_operators
-291222909838
+1245693242827665
 8
 1
 100
@@ -117,7 +117,7 @@ boolean_operators
 50
 
 boolop_loops
-9760565944591
+11270260636676715317
 9
 1
 50
@@ -130,14 +130,14 @@ boolop_loops
 26
 
 conditional_operator
-848
+54992
 3
 1
 0
 1
 
 do_fallthrough
-16586
+6898770640283947069
 4
 1
 10
@@ -145,12 +145,12 @@ do_fallthrough
 8
 
 main
-0
+24
 1
 1
 
 c-general.c:static_func
-4
+18129
 2
 1
 10

test/Profile/Inputs/c-unprofiled-blocks.proftext

@@ -1,5 +1,5 @@
 never_called
-44257542701577
+5644096560937528444
 9
 0
 0
@@ -12,12 +12,12 @@ never_called
 0
 
 main
-1
+24
 1
 1
 
 dead_code
-2859007309808137
+9636018207904213947
 10
 1
 0

test/Profile/Inputs/cxx-class.proftext

@@ -1,52 +1,52 @@
 _Z14simple_wrapperv
-4
+18129
 2
 1
 100
 
 main
-0
+24
 1
 1
 
 _ZN6SimpleD1Ev
-10
+42129
 2
 0
 0
 
 _ZN6SimpleD2Ev
-10
+42129
 2
 100
 99
 
 _ZN6Simple6methodEv
-10
+42129
 2
 100
 99
 
 _ZN6SimpleC1Ei
-10
+42129
 2
 0
 0
 
 _ZN6SimpleC2Ei
-10
+42129
 2
 100
 99
 
 _ZN7DerivedC1Ev
-10
+42129
 2
 100
 99
 
 _ZN7DerivedD2Ev
-10
+42129
 2
 100
 99

test/Profile/Inputs/cxx-hash-v2.proftext

@@ -0,0 +1,239 @@
+_Z11loop_returnv
+# Func Hash:
+1160721
+# Num Counters:
+2
+# Counter Values:
+0
+0
+
+_Z10loop_breakv
+# Func Hash:
+1160593
+# Num Counters:
+2
+# Counter Values:
+0
+0
+
+_Z8no_gotosv
+# Func Hash:
+1
+# Num Counters:
+2
+# Counter Values:
+0
+0
+
+_Z13loop_continuev
+# Func Hash:
+1160657
+# Num Counters:
+2
+# Counter Values:
+0
+0
+
+_Z18loop_after_if_elsev
+# Func Hash:
+11044458641
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z21consecutive_try_catchv
+# Func Hash:
+49221687100497
+# Num Counters:
+5
+# Counter Values:
+0
+0
+0
+0
+0
+
+_Z16nested_try_catchv
+# Func Hash:
+49147600487505
+# Num Counters:
+5
+# Counter Values:
+0
+0
+0
+0
+0
+
+_Z13indirect_gotov
+# Func Hash:
+1345
+# Num Counters:
+2
+# Counter Values:
+0
+0
+
+_Z17nested_for_rangesv
+# Func Hash:
+1332305
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z18loop_in_then_blockv
+# Func Hash:
+11040003281
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z22consecutive_for_rangesv
+# Func Hash:
+1380689
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z15consecutive_dosv
+# Func Hash:
+856273
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z11direct_gotov
+# Func Hash:
+1281
+# Num Counters:
+2
+# Counter Values:
+0
+0
+
+main
+# Func Hash:
+24
+# Num Counters:
+1
+# Counter Values:
+1
+
+_Z11double_lnotv
+# Func Hash:
+174695569
+# Num Counters:
+2
+# Counter Values:
+0
+0
+
+_Z18if_inside_of_whilev
+# Func Hash:
+36250705
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z11single_lnotv
+# Func Hash:
+2729105
+# Num Counters:
+2
+# Counter Values:
+0
+0
+
+_Z19if_outside_of_whilev
+# Func Hash:
+38053009
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z8no_throwv
+# Func Hash:
+0
+# Num Counters:
+1
+# Counter Values:
+0
+
+_Z9has_throwv
+# Func Hash:
+25
+# Num Counters:
+1
+# Counter Values:
+0
+
+_Z10nested_dosv
+# Func Hash:
+799825
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z16if_inside_of_forv
+# Func Hash:
+4750648401
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z18loop_in_else_blockv
+# Func Hash:
+11044398161
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z17if_outside_of_forv
+# Func Hash:
+4752450705
+# Num Counters:
+3
+# Counter Values:
+0
+0
+0
+
+_Z10loop_emptyv
+# Func Hash:
+18129
+# Num Counters:
+2
+# Counter Values:
+0
+0
+

test/Profile/Inputs/cxx-lambda.proftext

@@ -1,17 +1,17 @@
 cxx-lambda.cpp:_ZZ7lambdasvENK3$_0clEi
-654
+11211970062
 3
 10
 9
 9
 
 main
-0
+24
 1
 1
 
 _Z7lambdasv
-41226
+2895087587861649
 4
 1
 1

test/Profile/Inputs/cxx-rangefor.proftext

@@ -1,5 +1,5 @@
 _Z9range_forv
-0x000000000014a28a
+6169071350249721981
 5
 1
 4
@@ -8,6 +8,6 @@ _Z9range_forv
 1
 
 main
-0
+24
 1
 1

test/Profile/Inputs/cxx-templates.proftext

@@ -1,16 +1,16 @@
 main
-0
+24
 1
 1
 
 _Z4loopILj0EEvv
-4
+18129
 2
 1
 0
 
 _Z4loopILj100EEvv
-4
+18129
 2
 1
 100

test/Profile/Inputs/cxx-throws.proftext

@@ -1,5 +1,5 @@
 _Z6throwsv
-18359008150154
+340120998528097520
 9
 1
 100
@@ -12,14 +12,14 @@ _Z6throwsv
 100
 
 _Z11unreachablei
-0x28a
+706946049169
 3
 1
 1
 0
 
 main
-0x2cc
+187765848
 3
 1
 1

test/Profile/Inputs/func-entry.proftext

@@ -1,10 +1,10 @@
 foo
-0
+24
 1
 1000
 
 main
-4
+1160280
 2
 1
 10000

test/Profile/Inputs/gcc-flag-compatibility.proftext

@@ -1,5 +1,5 @@
 main
-4
+1160280
 2
 1
 100

test/Profile/Inputs/objc-general.proftext

@@ -1,17 +1,30 @@
 objc-general.m:__13+[A foreach:]_block_invoke
-10
+42129
 2
 2
 1
 
 objc-general.m:+[A foreach:]
-6
+401
 2
 1
 2
 
 main
-0
+24
 1
 1
 
+consecutive_objc_for_ranges
+1642897
+3
+0
+0
+0
+
+nested_objc_for_ranges
+1598545
+3
+0
+0
+0

test/Profile/c-outdated-data.c

@@ -7,10 +7,10 @@
 // RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name c-outdated-data.c %s -o /dev/null -emit-llvm -fprofile-instrument-use-path=%t.profdata 2>&1 | FileCheck %s -check-prefix=NO_MISSING
 // RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name c-outdated-data.c %s -o /dev/null -emit-llvm -Wprofile-instr-missing -fprofile-instrument-use-path=%t.profdata 2>&1 | FileCheck %s -check-prefix=WITH_MISSING
 
-// NO_MISSING: warning: profile data may be out of date: of 3 functions, 1 has mismatched data that will be ignored
+// NO_MISSING: warning: profile data may be out of date: of 3 functions, 2 have mismatched data that will be ignored
 // NO_MISSING-NOT: 1 has no data
 
-// WITH_MISSING: warning: profile data may be out of date: of 3 functions, 1 has mismatched data that will be ignored
+// WITH_MISSING: warning: profile data may be out of date: of 3 functions, 2 have mismatched data that will be ignored
 // WITH_MISSING: warning: profile data may be incomplete: of 3 functions, 1 has no data
 
 void no_usable_data() {

test/Profile/cxx-hash-v2.cpp

@@ -0,0 +1,177 @@
+// REQUIRES: shell
+
+// Check that all of the hashes in this file are unique (i.e, that none of the
+// profiles for these functions are mutually interchangeable).
+//
+// RUN: llvm-profdata show -all-functions %S/Inputs/cxx-hash-v2.profdata.v5 | grep "Hash: 0x" | sort > %t.hashes
+// RUN: uniq %t.hashes > %t.hashes.unique
+// RUN: diff %t.hashes %t.hashes.unique
+
+// RUN: llvm-profdata merge %S/Inputs/cxx-hash-v2.proftext -o %t.profdata
+// RUN: %clang_cc1 -std=c++11 -fexceptions -fcxx-exceptions -triple x86_64-apple-macosx10.9 -main-file-name cxx-hash-v2.mm %s -o /dev/null -emit-llvm -fprofile-instrument-use-path=%t.profdata 2>&1 | FileCheck %s -allow-empty
+// RUN: %clang_cc1 -std=c++11 -fexceptions -fcxx-exceptions -triple x86_64-apple-macosx10.9 -main-file-name cxx-hash-v2.mm %s -o /dev/null -emit-llvm -fprofile-instrument-use-path=%S/Inputs/cxx-hash-v2.profdata.v5 2>&1 | FileCheck %s -allow-empty
+
+// CHECK-NOT: warning: profile data may be out of date
+
+int x;
+int arr[1] = {0};
+
+void loop_after_if_else() {
+  if (1)
+    x = 1;
+  else
+    x = 2;
+  while (0)
+    ++x;
+}
+
+void loop_in_then_block() {
+  if (1) {
+    while (0)
+      ++x;
+  } else {
+    x = 2;
+  }
+}
+
+void loop_in_else_block() {
+  if (1) {
+    x = 1;
+  } else {
+    while (0)
+      ++x;
+  }
+}
+
+void if_inside_of_for() {
+  for (x = 0; x < 0; ++x) {
+    x = 1;
+    if (1)
+      x = 2;
+  }
+}
+
+void if_outside_of_for() {
+  for (x = 0; x < 0; ++x)
+    x = 1;
+  if (1)
+    x = 2;
+}
+
+void if_inside_of_while() {
+  while (0) {
+    x = 1;
+    if (1)
+      x = 2;
+  }
+}
+
+void if_outside_of_while() {
+  while (0)
+    x = 1;
+  if (1)
+    x = 2;
+}
+
+void nested_dos() {
+  do {
+    do {
+      ++x;
+    } while (0);
+  } while (0);
+}
+
+void consecutive_dos() {
+  do {
+  } while (0);
+  do {
+    ++x;
+  } while (0);
+}
+
+void loop_empty() {
+  for (x = 0; x < 5; ++x) {}
+}
+
+void loop_return() {
+  for (x = 0; x < 5; ++x)
+    return;
+}
+
+void loop_continue() {
+  for (x = 0; x < 5; ++x)
+    continue;
+}
+
+void loop_break() {
+  for (x = 0; x < 5; ++x)
+    break;
+}
+
+void no_gotos() {
+  static void *dispatch[] = {&&done};
+  x = 0;
+done:
+  ++x;
+}
+
+void direct_goto() {
+  static void *dispatch[] = {&&done};
+  x = 0;
+  goto done;
+done:
+  ++x;
+}
+
+void indirect_goto() {
+  static void *dispatch[] = {&&done};
+  x = 0;
+  goto *dispatch[x];
+done:
+  ++x;
+}
+
+void nested_for_ranges() {
+  for (int a : arr)
+    for (int b : arr)
+      ++x;
+}
+
+void consecutive_for_ranges() {
+  for (int a : arr) {}
+  for (int b : arr)
+    ++x;
+}
+
+void nested_try_catch() {
+  try {
+    try {
+      ++x;
+    } catch (...) {}
+  } catch (...) {}
+}
+
+void consecutive_try_catch() {
+  try {} catch (...) {}
+  try {
+    ++x;
+  } catch (...) {}
+}
+
+void no_throw() {}
+
+void has_throw() {
+  throw 0;
+}
+
+void single_lnot() {
+  if (!x) {}
+}
+
+void double_lnot() {
+  if (!!x) {}
+}
+
+int main() {
+  return 0;
+}

test/Profile/objc-general.m

@@ -3,7 +3,9 @@
 // RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name objc-general.m %s -o - -emit-llvm -fblocks -fprofile-instrument=clang | FileCheck -check-prefix=PGOGEN %s
 
 // RUN: llvm-profdata merge %S/Inputs/objc-general.proftext -o %t.profdata
-// RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name objc-general.m %s -o - -emit-llvm -fblocks -fprofile-instrument-use-path=%t.profdata | FileCheck -check-prefix=PGOUSE %s
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.9 -main-file-name objc-general.m %s -o - -emit-llvm -fblocks -fprofile-instrument-use-path=%t.profdata 2>&1 | FileCheck -check-prefix=PGOUSE %s
+
+// PGOUSE-NOT: warning: profile data may be out of date
 
 #ifdef HAVE_FOUNDATION
 
@@ -63,6 +65,20 @@ struct NSFastEnumerationState;
 }
 @end
 
+void nested_objc_for_ranges(NSArray *arr) {
+  int x = 0;
+  for (id a in arr)
+    for (id b in arr)
+      ++x;
+}
+
+void consecutive_objc_for_ranges(NSArray *arr) {
+  int x = 0;
+  for (id a in arr) {}
+  for (id b in arr)
+    ++x;
+}
+
 // PGOUSE-DAG: ![[FR1]] = !{!"branch_weights", i32 2, i32 3}
 // PGOUSE-DAG: ![[FR2]] = !{!"branch_weights", i32 3, i32 2}
 // PGOUSE-DAG: ![[BL1]] = !{!"branch_weights", i32 2, i32 2}