diff options
author | Alexey Bataev <a.bataev@hotmail.com> | 2017-12-12 20:28:46 +0000 |
---|---|---|
committer | Alexey Bataev <a.bataev@hotmail.com> | 2017-12-12 20:28:46 +0000 |
commit | c8f8b670873511636fb7fc56e14b08763fa5abca (patch) | |
tree | 63b5665cc8c04ba83068578cabc70375cc6451ac /lib | |
parent | ac78b4324b04deca9191bfa9d6a3c5d4b825aca6 (diff) |
[InstCombine] Fix PR35618: Instcombine hangs on single minmax load bitcast.
Summary:
If we have pattern `store (load(bitcast(select (cmp(V1, V2), &V1,
&V2)))), bitcast)`, but the load is used in other instructions, it leads
to looping in InstCombiner. Patch adds additional check that all users
of the load instructions are stores and then replaces all uses of load
instruction by the new one with new type.
Reviewers: RKSimon, spatel, majnemer
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41072
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320525 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp index 01fc1528681..713d540079f 100644 --- a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp +++ b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp @@ -1339,10 +1339,10 @@ static bool equivalentAddressValues(Value *A, Value *B) { /// Converts store (bitcast (load (bitcast (select ...)))) to /// store (load (select ...)), where select is minmax: /// select ((cmp load V1, load V2), V1, V2). -bool removeBitcastsFromLoadStoreOnMinMax(InstCombiner &IC, StoreInst &SI) { +static bool removeBitcastsFromLoadStoreOnMinMax(InstCombiner &IC, + StoreInst &SI) { // bitcast? - Value *StoreAddr; - if (!match(SI.getPointerOperand(), m_BitCast(m_Value(StoreAddr)))) + if (!match(SI.getPointerOperand(), m_BitCast(m_Value()))) return false; // load? integer? Value *LoadAddr; @@ -1354,9 +1354,25 @@ bool removeBitcastsFromLoadStoreOnMinMax(InstCombiner &IC, StoreInst &SI) { if (!isMinMaxWithLoads(LoadAddr)) return false; + if (!all_of(LI->users(), [LI, LoadAddr](User *U) { + auto *SI = dyn_cast<StoreInst>(U); + return SI && SI->getPointerOperand() != LI && + peekThroughBitcast(SI->getPointerOperand()) != LoadAddr && + !SI->getPointerOperand()->isSwiftError(); + })) + return false; + + IC.Builder.SetInsertPoint(LI); LoadInst *NewLI = combineLoadToNewType( IC, *LI, LoadAddr->getType()->getPointerElementType()); - combineStoreToNewValue(IC, SI, NewLI); + // Replace all the stores with stores of the newly loaded value. + for (auto *UI : LI->users()) { + auto *USI = cast<StoreInst>(UI); + IC.Builder.SetInsertPoint(USI); + combineStoreToNewValue(IC, *USI, NewLI); + } + IC.replaceInstUsesWith(*LI, UndefValue::get(LI->getType())); + IC.eraseInstFromFunction(*LI); return true; } |