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Improve logic that decides if its profitable to commute when some of the virtual registers involved have uses/defs chains connecting them to physical register. Fix up the tests that this change improves.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221336 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Craig Topper
2014-11-05 06:43:02 +00:00
parent 090bd82177
commit 04a45948a0
10 changed files with 57 additions and 81 deletions
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19
lib/CodeGen/TwoAddressInstructionPass.cpp
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@@ -545,10 +545,21 @@ isProfitableToCommute(unsigned regA, unsigned regB, unsigned regC,
if (ToRegA) {
unsigned FromRegB = getMappedReg(regB, SrcRegMap);
unsigned FromRegC = getMappedReg(regC, SrcRegMap);
bool BComp = !FromRegB || regsAreCompatible(FromRegB, ToRegA, TRI);
bool CComp = !FromRegC || regsAreCompatible(FromRegC, ToRegA, TRI);
if (BComp != CComp)
return !BComp && CComp;
bool CompB = FromRegB && regsAreCompatible(FromRegB, ToRegA, TRI);
bool CompC = FromRegC && regsAreCompatible(FromRegC, ToRegA, TRI);
// Compute if any of the following are true:
// -RegB is not tied to a register and RegC is compatible with RegA.
// -RegB is tied to the wrong physical register, but RegC is.
// -RegB is tied to the wrong physical register, and RegC isn't tied.
if ((!FromRegB && CompC) || (FromRegB && !CompB && (!FromRegC || CompC)))
return true;
// Don't compute if any of the following are true:
// -RegC is not tied to a register and RegB is compatible with RegA.
// -RegC is tied to the wrong physical register, but RegB is.
// -RegC is tied to the wrong physical register, and RegB isn't tied.
if ((!FromRegC && CompB) || (FromRegC && !CompC && (!FromRegB || CompB)))
return false;
}
// If there is a use of regC between its last def (could be livein) and this