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Fix a case where an earlyclobber operand of an asm

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is reused as an input.  PR 4118.  Testcase is too big,
as usual with bugs in this area, but there's one in
the PR.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106816 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen 2010-06-25 00:49:43 +00:00
parent a0ae87fd5d
commit 969b9fe379
1 changed files with 17 additions and 0 deletions
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17
lib/CodeGen/VirtRegRewriter.cpp
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@ -2033,6 +2033,21 @@ LocalRewriter::RewriteMBB(LiveIntervals *LIs,
CanReuse = !ReusedOperands.isClobbered(PhysReg) &&
Spills.canClobberPhysReg(PhysReg);
}
// If this is an asm, and PhysReg is used elsewhere as an earlyclobber
// operand, we can't also use it as an input. (Outputs always come
// before inputs, so we can stop looking at i.)
if (MI.getOpcode()==TargetOpcode::INLINEASM) {
for (unsigned k=0; k<i; ++k) {
MachineOperand &MOk = MI.getOperand(k);
if (!MOk.isReg() || MOk.getReg()==0)
continue;
unsigned VirtRegk = MOk.getReg();
if (VirtRegk == PhysReg && MOk.isEarlyClobber()) {
CanReuse = false;
break;
}
}
}
if (CanReuse) {
// If this stack slot value is already available, reuse it!
@ -2103,6 +2118,8 @@ LocalRewriter::RewriteMBB(LiveIntervals *LIs,
// To avoid this problem, and to avoid doing a load right after a store,
// we emit a copy from PhysReg into the designated register for this
// operand.
//
// This case also applies to an earlyclobber'd PhysReg.
unsigned DesignatedReg = VRM->getPhys(VirtReg);
assert(DesignatedReg && "Must map virtreg to physreg!");