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%.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45533 91177308-0d34-0410-b5e6-96231b3b80d8

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.
       }