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Handle register masks in MachineCopyPropagation.

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For simplicity, treat calls with register masks as basic block
boundaries.  This means we can't copy propagate callee-saved registers
across calls, but I don't think that is a big deal.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150108 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2012-02-08 22:37:35 +00:00
parent 54a4ce431f
commit a8fc171b3f
1 changed files with 17 additions and 0 deletions
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17
lib/CodeGen/MachineCopyPropagation.cpp
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@ -191,8 +191,11 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
// Not a copy.
SmallVector<unsigned, 2> Defs;
bool HasRegMask = false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (MO.isRegMask())
HasRegMask = true;
if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
@ -220,6 +223,20 @@ bool MachineCopyPropagation::CopyPropagateBlock(MachineBasicBlock &MBB) {
}
}
// The instruction has a register mask operand which means that it clobbers
// a large set of registers. It is possible to use the register mask to
// prune the available copies, but treat it like a basic block boundary for
// now.
if (HasRegMask) {
// FIXME: We could possibly erase some MaybeDeadCopies if their registers
// are clobbered by the mask.
MaybeDeadCopies.clear();
AvailCopyMap.clear();
CopyMap.clear();
SrcMap.clear();
continue;
}
for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
unsigned Reg = Defs[i];