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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-01-24 04:44:01 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-01-24 04:44:01 +0000 |
| commit | defe12df51249200214b7781ebe23345df474655 (patch) | |
| tree | ab29b2b8ab3b0303f043d5481a2099319e080ad5 /lib/CodeGen/TwoAddressInstructionPass.cpp | |
| parent | 45bb5c5333fba7e9909cca178d785bf2c1d2b0c1 (diff) | |
| download | llvm-defe12df51249200214b7781ebe23345df474655.tar.gz llvm-defe12df51249200214b7781ebe23345df474655.tar.bz2 llvm-defe12df51249200214b7781ebe23345df474655.tar.xz | |
Preserve <def,undef> flags in CoalesceExtSubRegs.
This won't have an effect until EliminateRegSequences() starts setting
the undef flags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148779 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/TwoAddressInstructionPass.cpp')
| -rw-r--r-- | lib/CodeGen/TwoAddressInstructionPass.cpp | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp index dc6b3420ab..8002ff2c64 100644 --- a/lib/CodeGen/TwoAddressInstructionPass.cpp +++ b/lib/CodeGen/TwoAddressInstructionPass.cpp @@ -1728,8 +1728,10 @@ TwoAddressInstructionPass::CoalesceExtSubRegs(SmallVector<unsigned,4> &Srcs, CanCoalesce = false; break; } - // Keep track of one of the uses. - SomeMI = UseMI; + // Keep track of one of the uses. Preferably the first one which has a + // <def,undef> flag. + if (!SomeMI || UseMI->getOperand(0).isUndef()) + SomeMI = UseMI; } if (!CanCoalesce) continue; @@ -1738,7 +1740,9 @@ TwoAddressInstructionPass::CoalesceExtSubRegs(SmallVector<unsigned,4> &Srcs, MachineInstr *CopyMI = BuildMI(*SomeMI->getParent(), SomeMI, SomeMI->getDebugLoc(), TII->get(TargetOpcode::COPY)) - .addReg(DstReg, RegState::Define, NewDstSubIdx) + .addReg(DstReg, RegState::Define | + getUndefRegState(SomeMI->getOperand(0).isUndef()), + NewDstSubIdx) .addReg(SrcReg, 0, NewSrcSubIdx); // Remove all the old extract instructions. |