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Convert EXTRACT_SUBREG to COPY when emitting machine instrs.

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EXTRACT_SUBREG no longer appears as a machine instruction. Use COPY instead.

Add isCopy() checks in many places using isMoveInstr() and isExtractSubreg().
The isMoveInstr hook will be removed later.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107879 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2010-07-08 16:40:22 +00:00
parent 5c00e07795
commit 0bc25f4040
18 changed files with 103 additions and 131 deletions
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8
lib/CodeGen/OptimizeExts.cpp
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@@ -128,12 +128,12 @@ bool OptimizeExts::OptimizeInstr(MachineInstr *MI, MachineBasicBlock *MBB,
//
// %reg1025 = <sext> %reg1024
// ...
// %reg1027 = EXTRACT_SUBREG %reg1025, 4
// %reg1027 = COPY %reg1025:4
// %reg1026 = SUBREG_TO_REG 0, %reg1027, 4
//
// The problem here is that SUBREG_TO_REG is there to assert that an
// implicit zext occurs. It doesn't insert a zext instruction. If we allow
// the EXTRACT_SUBREG here, it will give us the value after the <sext>,
// the COPY here, it will give us the value after the <sext>,
// not the original value of %reg1024 before <sext>.
if (UseMI->getOpcode() == TargetOpcode::SUBREG_TO_REG)
continue;
@@ -185,8 +185,8 @@ bool OptimizeExts::OptimizeInstr(MachineInstr *MI, MachineBasicBlock *MBB,
continue;
unsigned NewVR = MRI->createVirtualRegister(RC);
BuildMI(*UseMBB, UseMI, UseMI->getDebugLoc(),
TII->get(TargetOpcode::EXTRACT_SUBREG), NewVR)
.addReg(DstReg).addImm(SubIdx);
TII->get(TargetOpcode::COPY), NewVR)
.addReg(DstReg, 0, SubIdx);
UseMO->setReg(NewVR);
++NumReuse;
Changed = true;