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Fix ARM vector copies of overlapping register tuples.

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I have tested the fix, but have not been successfull in generating
a robust unit test. This can only be exposed through particular
register assignments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162821 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick 2012-08-29 01:58:55 +00:00
parent d79dedd458
commit f26e43df26
1 changed files with 13 additions and 0 deletions
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13
lib/Target/ARM/ARMBaseInstrInfo.cpp
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@ -710,10 +710,23 @@ void ARMBaseInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
const TargetRegisterInfo *TRI = &getRegisterInfo();
MachineInstrBuilder Mov;
// Copy register tuples backward when the first Dest reg overlaps with SrcReg.
if (TRI->regsOverlap(SrcReg, TRI->getSubReg(DestReg, BeginIdx))) {
BeginIdx = BeginIdx + ((SubRegs-1)*Spacing);
Spacing = -Spacing;
}
#ifndef NDEBUG
SmallSet<unsigned, 4> DstRegs;
#endif
for (unsigned i = 0; i != SubRegs; ++i) {
unsigned Dst = TRI->getSubReg(DestReg, BeginIdx + i*Spacing);
unsigned Src = TRI->getSubReg(SrcReg, BeginIdx + i*Spacing);
assert(Dst && Src && "Bad sub-register");
#ifndef NDEBUG
DstRegs.insert(Dst);
assert(!DstRegs.count(Src) && "destructive vector copy");
#endif
Mov = BuildMI(MBB, I, I->getDebugLoc(), get(Opc), Dst)
.addReg(Src);
// VORR takes two source operands.