diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/CodeGen/MachineBasicBlock.cpp | 11 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/cmpxchg-clobber-flags.ll | 3 |
2 files changed, 10 insertions, 4 deletions
diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp index 8b3f01fe58c..58e71bbe2e2 100644 --- a/llvm/lib/CodeGen/MachineBasicBlock.cpp +++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp @@ -1208,8 +1208,15 @@ MachineBasicBlock::computeRegisterLiveness(const TargetRegisterInfo *TRI, if (Info.DeadDef) return LQR_Dead; // Register is (at least partially) live after a def. - if (Info.Defined) - return LQR_Live; + if (Info.Defined) { + if (!Info.PartialDeadDef) + return LQR_Live; + // As soon as we saw a partial definition (dead or not), + // we cannot tell if the value is partial live without + // tracking the lanemasks. We are not going to do this, + // so fall back on the remaining of the analysis. + break; + } // Register is dead after a full kill or clobber and no def. if (Info.Killed || Info.Clobbered) return LQR_Dead; diff --git a/llvm/test/CodeGen/X86/cmpxchg-clobber-flags.ll b/llvm/test/CodeGen/X86/cmpxchg-clobber-flags.ll index 74599cbdc17..f2b9dee9103 100644 --- a/llvm/test/CodeGen/X86/cmpxchg-clobber-flags.ll +++ b/llvm/test/CodeGen/X86/cmpxchg-clobber-flags.ll @@ -167,11 +167,10 @@ define i32 @test_feed_cmov(i32* %addr, i32 %desired, i32 %new) { ; x8664-sahf-LABEL: test_feed_cmov: ; x8664-sahf: cmpxchgl -; x8664-sahf: pushq %rax +; RAX is dead, do not push or pop it. ; 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 |
