[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, 15 insertions, 17 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 815af57fc7a..bd319ef83df 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -251,22 +251,20 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
     }
   }
 
+  if (Instruction *FoldedMul = foldBinOpIntoSelectOrPhi(I))
+    return FoldedMul;
+
   // Simplify mul instructions with a constant RHS.
   if (isa<Constant>(Op1)) {
-    if (Instruction *FoldedMul = foldOpWithConstantIntoOperand(I))
-      return FoldedMul;
-
     // Canonicalize (X+C1)*CI -> X*CI+C1*CI.
-    {
-      Value *X;
-      Constant *C1;
-      if (match(Op0, m_OneUse(m_Add(m_Value(X), m_Constant(C1))))) {
-        Value *Mul = Builder.CreateMul(C1, Op1);
-        // Only go forward with the transform if C1*CI simplifies to a tidier
-        // constant.
-        if (!match(Mul, m_Mul(m_Value(), m_Value())))
-          return BinaryOperator::CreateAdd(Builder.CreateMul(X, Op1), Mul);
-      }
+    Value *X;
+    Constant *C1;
+    if (match(Op0, m_OneUse(m_Add(m_Value(X), m_Constant(C1))))) {
+      Value *Mul = Builder.CreateMul(C1, Op1);
+      // Only go forward with the transform if C1*CI simplifies to a tidier
+      // constant.
+      if (!match(Mul, m_Mul(m_Value(), m_Value())))
+        return BinaryOperator::CreateAdd(Builder.CreateMul(X, Op1), Mul);
     }
   }
 
@@ -555,11 +553,11 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
 
   bool AllowReassociate = I.isFast();
 
+  if (Instruction *FoldedMul = foldBinOpIntoSelectOrPhi(I))
+    return FoldedMul;
+
   // Simplify mul instructions with a constant RHS.
   if (auto *C = dyn_cast<Constant>(Op1)) {
-    if (Instruction *FoldedMul = foldOpWithConstantIntoOperand(I))
-      return FoldedMul;
-
     // -X * C --> X * -C
     Value *X;
     if (match(Op0, m_FNeg(m_Value(X))))
@@ -900,7 +898,7 @@ Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
     }
 
     if (!C2->isNullValue()) // avoid X udiv 0
-      if (Instruction *FoldedDiv = foldOpWithConstantIntoOperand(I))
+      if (Instruction *FoldedDiv = foldBinOpIntoSelectOrPhi(I))
         return FoldedDiv;
   }