Use TII->findCommutedOpIndices to find the commute operands (rather than guessing).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76472 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 83468d9..ebdf9cf 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -879,10 +879,14 @@
// so, swap the B and C operands. This makes the live ranges of A
// and C joinable.
// FIXME: This code also works for A := B op C instructions.
- if (TID.isCommutable() && mi->getNumOperands() >= 3) {
- assert(mi->getOperand(3-si).isReg() &&
- "Not a proper commutative instruction!");
- unsigned regC = mi->getOperand(3-si).getReg();
+ unsigned SrcOp1, SrcOp2;
+ if (TID.isCommutable() && mi->getNumOperands() >= 3 &&
+ TII->findCommutedOpIndices(mi, SrcOp1, SrcOp2)) {
+ unsigned regC = 0;
+ if (si == SrcOp1)
+ regC = mi->getOperand(SrcOp2).getReg();
+ else if (si == SrcOp2)
+ regC = mi->getOperand(SrcOp1).getReg();
if (isKilled(*mi, regC, MRI, TII)) {
if (CommuteInstruction(mi, mbbi, regB, regC, Dist)) {
++NumCommuted;