Canonicalize ConstantInts to the right operand of commutative

operators.

The test difference is just due to the multiplication operands
being commuted (and thus requiring a more elaborate match). In
optimized code, that expression would be folded.

llvm-svn: 96816

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/VMCore/ConstantFold.cpp b/llvm/lib/VMCore/ConstantFold.cpp
index c79eb7ef2c9..36b307ce881 100644
--- a/llvm/lib/VMCore/ConstantFold.cpp
+++ b/llvm/lib/VMCore/ConstantFold.cpp
@@ -1105,6 +1105,10 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
           return ConstantExpr::getLShr(C1, C2);
       break;
     }
+  } else if (isa<ConstantInt>(C1)) {
+    // If C1 is a ConstantInt and C2 is not, swap the operands.
+    if (Instruction::isCommutative(Opcode))
+      return ConstantExpr::get(Opcode, C2, C1);
   }
 
   // At this point we know neither constant is an UndefValue.