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.
llvm-svn: 221336
diff --git a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
index 4ed9bf2..428846a 100644
--- a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -545,10 +545,21 @@
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