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[TwoAddressInstructionPass] Bugfix in handling of sunk instructions.

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An instruction returned by TII->convertToThreeAddress() may contain a %noreg
(undef) operand, which is not expected by tryInstructionTransform(). So if
this MI is sunk to a lower point in MBB, it must be skipped when later
encountered.

A new set SunkInstrs is used for this purpose.

Note: there is no test supplied here, as this was triggered on SystemZ while
working on a review of instruction flags. A test case for this bugfix will be
included in the upcoming SystemZ commit.

Review: Quentin Colombet
https://reviews.llvm.org/D40711

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319646 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jonas Paulsson 2017-12-04 10:03:14 +00:00
parent 5022455191
commit 62f11d908e
1 changed files with 10 additions and 1 deletions
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11
lib/CodeGen/TwoAddressInstructionPass.cpp
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@ -110,6 +110,10 @@ class TwoAddressInstructionPass : public MachineFunctionPass {
// Set of already processed instructions in the current block.
SmallPtrSet<MachineInstr*, 8> Processed;
// Set of instructions converted to three-address by target and then sunk
// down current basic block.
SmallPtrSet<MachineInstr*, 8> SunkInstrs;
// A map from virtual registers to physical registers which are likely targets
// to be coalesced to due to copies from physical registers to virtual
// registers. e.g. v1024 = move r0.
@ -756,6 +760,8 @@ TwoAddressInstructionPass::convertInstTo3Addr(MachineBasicBlock::iterator &mi,
mi = NewMI;
nmi = std::next(mi);
}
else
SunkInstrs.insert(NewMI);
// Update source and destination register maps.
SrcRegMap.erase(RegA);
@ -1674,10 +1680,13 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &Func) {
SrcRegMap.clear();
DstRegMap.clear();
Processed.clear();
SunkInstrs.clear();
for (MachineBasicBlock::iterator mi = MBB->begin(), me = MBB->end();
mi != me; ) {
MachineBasicBlock::iterator nmi = std::next(mi);
if (mi->isDebugValue()) {
// Don't revisit an instruction previously converted by target. It may
// contain undef register operands (%noreg), which are not handled.
if (mi->isDebugValue() || SunkInstrs.count(&*mi)) {
mi = nmi;
continue;
}