diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp index 12566922c83..aca014f04cd 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp @@ -1038,9 +1038,9 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) { return &SI; } - // Don't hack volatile/atomic stores. - // FIXME: Some bits are legal for atomic stores; needs refactoring. - if (!SI.isSimple()) return nullptr; + // Don't hack volatile/ordered stores. + // FIXME: Some bits are legal for ordered atomic stores; needs refactoring. + if (!SI.isUnordered()) return nullptr; // If the RHS is an alloca with a single use, zapify the store, making the // alloca dead. @@ -1072,7 +1072,7 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) { if (StoreInst *PrevSI = dyn_cast<StoreInst>(BBI)) { // Prev store isn't volatile, and stores to the same location? - if (PrevSI->isSimple() && equivalentAddressValues(PrevSI->getOperand(1), + if (PrevSI->isUnordered() && equivalentAddressValues(PrevSI->getOperand(1), SI.getOperand(1))) { ++NumDeadStore; ++BBI; @@ -1086,9 +1086,10 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) { // the pointer we're loading and is producing the pointer we're storing, // then *this* store is dead (X = load P; store X -> P). if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) { - if (LI == Val && equivalentAddressValues(LI->getOperand(0), Ptr) && - LI->isSimple()) + if (LI == Val && equivalentAddressValues(LI->getOperand(0), Ptr)) { + assert(SI.isUnordered() && "can't eliminate ordering operation"); return EraseInstFromFunction(SI); + } // Otherwise, this is a load from some other location. Stores before it // may not be dead. @@ -1114,6 +1115,10 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) { if (isa<UndefValue>(Val)) return EraseInstFromFunction(SI); + // The code below needs to be audited and adjusted for unordered atomics + if (!SI.isSimple()) + return nullptr; + // If this store is the last instruction in the basic block (possibly // excepting debug info instructions), and if the block ends with an // unconditional branch, try to move it to the successor block. |
