diff options
| author | Eli Friedman <eli.friedman@gmail.com> | 2011-04-02 22:45:17 +0000 |
|---|---|---|
| committer | Eli Friedman <eli.friedman@gmail.com> | 2011-04-02 22:45:17 +0000 |
| commit | 71ad2c9eda710bc26ec1621a9afefad11dd7fad2 (patch) | |
| tree | 9854a19c8acd95da320530173701c38eb6b5cfac | |
| parent | 6bdd261df972b5e70e4242721ab16b57c6fe3d1f (diff) | |
PR9446: RecursivelyDeleteTriviallyDeadInstructions can delete the instruction
after the given instruction; make sure to handle that case correctly.
(It's difficult to trigger; the included testcase involves a dead
block, but I don't think that's a requirement.)
While I'm here, get rid of the unnecessary warning about
SimplifyInstructionsInBlock, since it should work correctly as far as I know.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128782 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | include/llvm/Transforms/Utils/Local.h | 4 | ||||
| -rw-r--r-- | lib/Transforms/Utils/Local.cpp | 5 | ||||
| -rw-r--r-- | test/Transforms/JumpThreading/2011-04-02-SimplifyDeadBlock.ll | 32 |
3 files changed, 36 insertions, 5 deletions
diff --git a/include/llvm/Transforms/Utils/Local.h b/include/llvm/Transforms/Utils/Local.h index f63796c4ea..e61dcb347c 100644 --- a/include/llvm/Transforms/Utils/Local.h +++ b/include/llvm/Transforms/Utils/Local.h @@ -74,10 +74,6 @@ bool RecursivelyDeleteDeadPHINode(PHINode *PN); /// /// This returns true if it changed the code, note that it can delete /// instructions in other blocks as well in this block. -/// -/// WARNING: Do not use this function on unreachable blocks, as recursive -/// simplification is not able to handle corner-case scenarios that can -/// arise in them. bool SimplifyInstructionsInBlock(BasicBlock *BB, const TargetData *TD = 0); //===----------------------------------------------------------------------===// diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp index 47ef1c9174..26ae295d5d 100644 --- a/lib/Transforms/Utils/Local.cpp +++ b/lib/Transforms/Utils/Local.cpp @@ -332,8 +332,11 @@ bool llvm::SimplifyInstructionsInBlock(BasicBlock *BB, const TargetData *TD) { BI = BB->begin(); continue; } - + + WeakVH BIHandle(BI); MadeChange |= RecursivelyDeleteTriviallyDeadInstructions(Inst); + if (BIHandle != BI) + BI = BB->begin(); } return MadeChange; } diff --git a/test/Transforms/JumpThreading/2011-04-02-SimplifyDeadBlock.ll b/test/Transforms/JumpThreading/2011-04-02-SimplifyDeadBlock.ll new file mode 100644 index 0000000000..76dd2d12bd --- /dev/null +++ b/test/Transforms/JumpThreading/2011-04-02-SimplifyDeadBlock.ll @@ -0,0 +1,32 @@ +; RUN: opt < %s -jump-threading +; PR9446 +; Just check that it doesn't crash + +define void @int327() nounwind { +entry: + unreachable + +for.cond: ; preds = %for.cond4 + %tobool3 = icmp eq i8 undef, 0 + br i1 %tobool3, label %for.cond23, label %for.cond4 + +for.cond4: ; preds = %for.cond + br label %for.cond + +for.cond23: ; preds = %for.body28, %for.cond23, %for.cond + %conv321 = phi i32 [ %conv32, %for.body28 ], [ 0, %for.cond ], [ %conv321, %for.cond23 ] + %l_266.0 = phi i32 [ %phitmp, %for.body28 ], [ 0, %for.cond ], [ 0, %for.cond23 ] + %cmp26 = icmp eq i32 %l_266.0, 0 + br i1 %cmp26, label %for.body28, label %for.cond23 + +for.body28: ; preds = %for.cond23 + %and = and i32 %conv321, 1 + %conv32 = zext i8 undef to i32 + %add = add nsw i32 %l_266.0, 1 + %phitmp = and i32 %add, 255 + br label %for.cond23 + +if.end43: ; No predecessors! + ret void +} + |