[LICM] Avoid repeating expensive call while promoting loads. NFC

Summary:
We can avoid repeating the check `isGuaranteedToExecute` when it's already called once while checking if the alignment can be widened for the load/store being hoisted.

The function is invariant for the same instruction `UI` in `isGuaranteedToExecute(*UI, DT, CurLoop, SafetyInfo);`

Reviewers: hfinkel, eli.friedman

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D21672

llvm-svn: 273671

llvm/lib/Transforms/Scalar/LICM.cpp

@@ -945,15 +945,16 @@ bool llvm::promoteLoopAccessesToScalars(
         // instruction will be executed, update the alignment.
         // Larger is better, with the exception of 0 being the best alignment.
         unsigned InstAlignment = Store->getAlignment();
-        if ((InstAlignment > Alignment || InstAlignment == 0) && Alignment != 0)
+        if ((InstAlignment > Alignment || InstAlignment == 0) &&
+            Alignment != 0) {
           if (isGuaranteedToExecute(*UI, DT, CurLoop, SafetyInfo)) {
             GuaranteedToExecute = true;
             Alignment = InstAlignment;
           }
-
-        if (!GuaranteedToExecute)
+        } else if (!GuaranteedToExecute) {
           GuaranteedToExecute =
               isGuaranteedToExecute(*UI, DT, CurLoop, SafetyInfo);
+        }
 
         if (!GuaranteedToExecute && !CanSpeculateLoad) {
           CanSpeculateLoad = isDereferenceableAndAlignedPointer(