[JumpThreading] Don't forget to report that the IR changed
JumpThreading's runOnFunction is supposed to return true if it made any
changes. JumpThreading has a call to removeUnreachableBlocks which may
result in changes to the IR but runOnFunction didn't appropriate account
for this possibility, leading to badness.
While we are here, make sure to call LazyValueInfo::eraseBlock in
removeUnreachableBlocks; JumpThreading preserves LVI.
This fixes PR26096.
llvm-svn: 257279
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 0e386ac..e4310c79 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -23,6 +23,7 @@
#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
+#include "llvm/Analysis/LazyValueInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
@@ -1407,7 +1408,7 @@
/// removeUnreachableBlocksFromFn - Remove blocks that are not reachable, even
/// if they are in a dead cycle. Return true if a change was made, false
/// otherwise.
-bool llvm::removeUnreachableBlocks(Function &F) {
+bool llvm::removeUnreachableBlocks(Function &F, LazyValueInfo *LVI) {
SmallPtrSet<BasicBlock*, 128> Reachable;
bool Changed = markAliveBlocks(F, Reachable);
@@ -1428,6 +1429,8 @@
++SI)
if (Reachable.count(*SI))
(*SI)->removePredecessor(&*BB);
+ if (LVI)
+ LVI->eraseBlock(&*BB);
BB->dropAllReferences();
}