[InstCombine] move constant check into foldBinOpIntoSelectOrPhi; NFCI

Also, rename 'foldOpWithConstantIntoOperand' because that's annoyingly 
vague. The constant check is redundant in some cases, but it allows 
removing duplication for most of the calls.

llvm-svn: 326329

1 files changed, 3 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 2f64c655c08..c47ebb34087 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -964,7 +964,7 @@ Instruction *InstCombiner::foldAddWithConstant(BinaryOperator &Add) {
   if (!match(Op1, m_Constant(Op1C)))
     return nullptr;
 
-  if (Instruction *NV = foldOpWithConstantIntoOperand(Add))
+  if (Instruction *NV = foldBinOpIntoSelectOrPhi(Add))
     return NV;
 
   Value *X;
@@ -1304,9 +1304,8 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
                                   SQ.getWithInstruction(&I)))
     return replaceInstUsesWith(I, V);
 
-  if (isa<Constant>(RHS))
-    if (Instruction *FoldedFAdd = foldOpWithConstantIntoOperand(I))
-      return FoldedFAdd;
+  if (Instruction *FoldedFAdd = foldBinOpIntoSelectOrPhi(I))
+    return FoldedFAdd;
 
   // -A + B  -->  B - A
   if (Value *LHSV = dyn_castFNegVal(LHS))