vendor/llvm/llvm-trunk-r300890

1 files changed, 12 insertions, 2 deletions

diff --git a/lib/Transforms/Scalar/StructurizeCFG.cpp b/lib/Transforms/Scalar/StructurizeCFG.cpp
index 49ce0262c97b..659353e912fe 100644
--- a/lib/Transforms/Scalar/StructurizeCFG.cpp
+++ b/lib/Transforms/Scalar/StructurizeCFG.cpp
@@ -352,10 +352,20 @@ Value *StructurizeCFG::invert(Value *Condition) {
   if (Instruction *Inst = dyn_cast<Instruction>(Condition)) {
     // Third: Check all the users for an invert
     BasicBlock *Parent = Inst->getParent();
-    for (User *U : Condition->users())
-      if (Instruction *I = dyn_cast<Instruction>(U))
+    for (User *U : Condition->users()) {
+      if (Instruction *I = dyn_cast<Instruction>(U)) {
         if (I->getParent() == Parent && match(I, m_Not(m_Specific(Condition))))
           return I;
+      }
+    }
+
+    // Avoid creating a new instruction in the common case of a compare.
+    if (CmpInst *Cmp = dyn_cast<CmpInst>(Inst)) {
+      if (Cmp->hasOneUse()) {
+        Cmp->setPredicate(Cmp->getInversePredicate());
+        return Cmp;
+      }
+    }
 
     // Last option: Create a new instruction
     return BinaryOperator::CreateNot(Condition, "", Parent->getTerminator());