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

2 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index f3f9a5102f8..1d23fe0b6c9 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -794,8 +794,8 @@ Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
         // it is casted back to a pointer, see if the expression can be
         // converted into a GEP.
         if (CE->getOpcode() == Instruction::Add)
-          if (ConstantInt *L = dyn_cast<ConstantInt>(CE->getOperand(0)))
-            if (ConstantExpr *R = dyn_cast<ConstantExpr>(CE->getOperand(1)))
+          if (ConstantInt *L = dyn_cast<ConstantInt>(CE->getOperand(1)))
+            if (ConstantExpr *R = dyn_cast<ConstantExpr>(CE->getOperand(0)))
               if (R->getOpcode() == Instruction::PtrToInt)
                 if (GlobalVariable *GV =
                       dyn_cast<GlobalVariable>(R->getOperand(0))) {
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.