MachineInstrBundle: Fix reversed isSuperRegisterEq() call

Unfortunately this fix had the effect of exposing the
-verify-machineinstrs FIXME of X86InstrInfo.cpp in two testcases for
which I disabled it for now.
Two testcases also have additional pushq/popq where the corrected code
cannot prove that %rax is dead any longer. Looking at the examples, this
could potentially be fixed by improving computeRegisterLiveness() to check
the live-in lists of the successors blocks when reaching the end of a
block.

This fixes http://llvm.org/PR25951.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256799 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineInstrBundle.cpp

@@ -315,7 +315,7 @@ MachineOperandIteratorBase::analyzePhysReg(unsigned Reg,
     if (!TRI->regsOverlap(MOReg, Reg))
       continue;
 
-    bool Covered = TRI->isSuperRegisterEq(MOReg, Reg);
+    bool Covered = TRI->isSuperRegisterEq(Reg, MOReg);
     if (MO.readsReg()) {
       PRI.Read = true;
       if (Covered) {

lib/Target/X86/X86InstrInfo.cpp

@@ -4466,6 +4466,10 @@ void X86InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
       // (unnecessarily) saving+restoring a dead register. However the
       // MachineVerifier expects operands that read from dead registers
       // to be marked with the "undef" flag.
+      // An example of this can be found in
+      // test/CodeGen/X86/peephole-na-phys-copy-folding.ll and
+      // test/CodeGen/X86/cmpxchg-clobber-flags.ll when using
+      // -verify-machineinstrs.
       BuildMI(MBB, MI, DL, get(Push)).addReg(AX, getKillRegState(true));
     }
     if (FromEFLAGS) {

test/CodeGen/X86/cmpxchg-clobber-flags.ll

@@ -1,11 +1,14 @@
-; RUN: llc -verify-machineinstrs -mtriple=i386-linux-gnu %s -o - | FileCheck %s -check-prefix=i386
-; RUN: llc -verify-machineinstrs -mtriple=i386-linux-gnu -pre-RA-sched=fast %s -o - | FileCheck %s -check-prefix=i386f
+; RUN: llc -mtriple=i386-linux-gnu %s -o - | FileCheck %s -check-prefix=i386
+; RUN: llc -mtriple=i386-linux-gnu -pre-RA-sched=fast %s -o - | FileCheck %s -check-prefix=i386f
 
-; RUN: llc -verify-machineinstrs -mtriple=x86_64-linux-gnu %s -o - | FileCheck %s -check-prefix=x8664
-; RUN: llc -verify-machineinstrs -mtriple=x86_64-linux-gnu -pre-RA-sched=fast %s -o - | FileCheck %s -check-prefix=x8664
-; RUN: llc -verify-machineinstrs -mtriple=x86_64-linux-gnu -mattr=+sahf %s -o - | FileCheck %s -check-prefix=x8664-sahf
-; RUN: llc -verify-machineinstrs -mtriple=x86_64-linux-gnu -mattr=+sahf -pre-RA-sched=fast %s -o - | FileCheck %s -check-prefix=x8664-sahf
-; RUN: llc -verify-machineinstrs -mtriple=x86_64-linux-gnu -mcpu=corei7 %s -o - | FileCheck %s -check-prefix=x8664-sahf
+; RUN: llc -mtriple=x86_64-linux-gnu %s -o - | FileCheck %s -check-prefix=x8664
+; RUN: llc -mtriple=x86_64-linux-gnu -pre-RA-sched=fast %s -o - | FileCheck %s -check-prefix=x8664
+; RUN: llc -mtriple=x86_64-linux-gnu -mattr=+sahf %s -o - | FileCheck %s -check-prefix=x8664-sahf
+; RUN: llc -mtriple=x86_64-linux-gnu -mattr=+sahf -pre-RA-sched=fast %s -o - | FileCheck %s -check-prefix=x8664-sahf
+; RUN: llc -mtriple=x86_64-linux-gnu -mcpu=corei7 %s -o - | FileCheck %s -check-prefix=x8664-sahf
+
+; TODO: Reenable verify-machineinstr once the if (!AXDead) // FIXME
+; in X86InstrInfo::copyPhysReg() is resolved.
 
 declare i32 @foo()
 declare i32 @bar(i64)
@@ -58,9 +61,11 @@ define i64 @test_intervening_call(i64* %foo, i64 %bar, i64 %baz) {
 ; x8664-sahf-NEXT: popq %rax
 ; x8664-sahf-NEXT: movq %rax, %rdi
 ; x8664-sahf-NEXT: callq bar
+; x8664-sahf-NEXT: pushq %rax
 ; x8664-sahf-NEXT: movq [[FLAGS]], %rax
 ; x8664-sahf-NEXT: addb $127, %al
 ; x8664-sahf-NEXT: sahf
+; x8664-sahf-NEXT: popq %rax
 ; x8664-sahf-NEXT: jne
 
   %cx = cmpxchg i64* %foo, i64 %bar, i64 %baz seq_cst seq_cst
@@ -161,9 +166,11 @@ define i32 @test_feed_cmov(i32* %addr, i32 %desired, i32 %new) {
 
 ; x8664-sahf-LABEL: test_feed_cmov:
 ; x8664-sahf: cmpxchgl
-; x8664-sahf: seto %al
+; x8664-sahf: pushq %rax
+; x8664-sahf-NEXT: seto %al
 ; x8664-sahf-NEXT: lahf
 ; x8664-sahf-NEXT: movq %rax, [[FLAGS:%.*]]
+; x8664-sahf-NEXT: popq %rax
 ; x8664-sahf-NEXT: callq foo
 ; x8664-sahf-NEXT: pushq %rax
 ; x8664-sahf-NEXT: movq [[FLAGS]], %rax

test/CodeGen/X86/peephole-na-phys-copy-folding.ll

@@ -1,5 +1,8 @@
-; RUN: llc -verify-machineinstrs -mtriple=i386-linux-gnu %s -o - | FileCheck %s
-; RUN: llc -verify-machineinstrs -mtriple=x86_64-linux-gnu -mattr=+sahf %s -o - | FileCheck %s
+; RUN: llc -mtriple=i386-linux-gnu %s -o - | FileCheck %s
+; RUN: llc -mtriple=x86_64-linux-gnu -mattr=+sahf %s -o - | FileCheck %s
+
+; TODO: Reenable verify-machineinstrs once the if (!AXDead) // FIXME in
+; X86InstrInfo::copyPhysReg() is resolved.
 
 ; The peephole optimizer can elide some physical register copies such as
 ; EFLAGS. Make sure the flags are used directly, instead of needlessly using