don't hoist FP additions into unconditional adds + selects. This

could theoretically introduce a trap, but is also a performance issue.
This speeds up ptrdist/ks by 8%.

llvm-svn: 45533

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index b838f94b790..f19adbd263c 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -372,6 +372,8 @@ static bool DominatesMergePoint(Value *V, BasicBlock *BB,
       case Instruction::AShr:
       case Instruction::ICmp:
       case Instruction::FCmp:
+        if (I->getOperand(0)->getType()->isFPOrFPVector())
+          return false;  // FP arithmetic might trap.
         break;   // These are all cheap and non-trapping instructions.
       }