[Sink] Fix predicate in legality check
Summary:
isSafeToSpeculativelyExecute is the wrong predicate to use here.
All that checks for is whether it is safe to hoist a value due to
unaligned/un-dereferencable accesses. However, not only are we doing
sinking rather than hoisting, our concern is that the location
we're loading from may have been modified. Instead forbid sinking
any load across a critical edge.
Reviewers: majnemer
Subscribers: davide, llvm-commits
Differential Revision: https://reviews.llvm.org/D33179
llvm-svn: 305102
diff --git a/llvm/lib/Transforms/Scalar/Sink.cpp b/llvm/lib/Transforms/Scalar/Sink.cpp
index 102e9ea..5210f16 100644
--- a/llvm/lib/Transforms/Scalar/Sink.cpp
+++ b/llvm/lib/Transforms/Scalar/Sink.cpp
@@ -114,7 +114,7 @@
if (SuccToSinkTo->getUniquePredecessor() != Inst->getParent()) {
// We cannot sink a load across a critical edge - there may be stores in
// other code paths.
- if (!isSafeToSpeculativelyExecute(Inst))
+ if (isa<LoadInst>(Inst))
return false;
// We don't want to sink across a critical edge if we don't dominate the