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 83468d9273d594a2cce93332b22ad89d0138cfe8..ebdf9cf4468b8dfa44660a1dc4a13f8f882509f2 100644 (file)
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -879,10 +879,14 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
             // 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;

diff --git a/test/CodeGen/Thumb/2009-07-20-TwoAddrBug.ll b/test/CodeGen/Thumb/2009-07-20-TwoAddrBug.ll
new file mode 100644 (file)
index 0000000..3e18d29
--- /dev/null
+++ b/test/CodeGen/Thumb/2009-07-20-TwoAddrBug.ll
@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s | llc -mtriple=thumbv6-apple-darwin10
+
+@Time.2535 = external global i64               ; <i64*> [#uses=2]
+
+define arm_apcscc i64 @millisecs() nounwind {
+entry:
+       %0 = load i64* @Time.2535, align 4              ; <i64> [#uses=2]
+       %1 = add i64 %0, 1              ; <i64> [#uses=1]
+       store i64 %1, i64* @Time.2535, align 4
+       ret i64 %0
+}