improve comment and drop a dead check. If PH had
no uses, it would have been deleted by
RecursivelyDeleteTriviallyDeadInstructions
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100275 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index b5fdd0c..650231b 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -759,10 +759,14 @@
Incr->replaceAllUsesWith(UndefValue::get(Incr->getType()));
RecursivelyDeleteTriviallyDeadInstructions(Incr);
- // Replace floating induction variable, if it isn't already deleted.
- // Give SIToFPInst preference over UIToFPInst because it is faster on
- // platforms that are widely used.
- if (WeakPH && !PH->use_empty()) {
+ // If the FP induction variable still has uses, this is because something else
+ // in the loop uses its value. In order to canonicalize the induction
+ // variable, we chose to eliminate the IV and rewrite it in terms of an
+ // int->fp cast.
+ //
+ // We give preference to sitofp over uitofp because it is faster on most
+ // platforms.
+ if (WeakPH) {
if (CanUseSIToFP(InitValueVal, ExitValueVal, InitValue, ExitValue)) {
SIToFPInst *Conv = new SIToFPInst(NewPHI, PH->getType(), "indvar.conv",
PH->getParent()->getFirstNonPHI());