diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Analysis/Loads.cpp | 43 | ||||
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp | 24 |
2 files changed, 17 insertions, 50 deletions
diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp index 1a2f8e76c87..309a1d95efb 100644 --- a/llvm/lib/Analysis/Loads.cpp +++ b/llvm/lib/Analysis/Loads.cpp @@ -297,17 +297,27 @@ llvm::DefMaxInstsToScan("available-load-scan-limit", cl::init(6), cl::Hidden, "to scan backward from a given instruction, when searching for " "available loaded value")); - -Value *llvm::FindAvailableLoadedValue(Value *Ptr, Type *AccessTy, - bool IsAtomicMemOp, BasicBlock *ScanBB, +Value *llvm::FindAvailableLoadedValue(LoadInst *Load, BasicBlock *ScanBB, BasicBlock::iterator &ScanFrom, unsigned MaxInstsToScan, AliasAnalysis *AA, AAMDNodes *AATags, bool *IsLoadCSE) { - if (MaxInstsToScan == 0) MaxInstsToScan = ~0U; + + Value *Ptr = Load->getPointerOperand(); + Type *AccessTy = Load->getType(); + + // We can never remove a volatile load + if (Load->isVolatile()) + return nullptr; + + // Anything stronger than unordered is currently unimplemented. + if (!Load->isUnordered()) + return nullptr; + const DataLayout &DL = ScanBB->getModule()->getDataLayout(); + // Try to get the store size for the type. uint64_t AccessSize = DL.getTypeStoreSize(AccessTy); @@ -338,7 +348,7 @@ Value *llvm::FindAvailableLoadedValue(Value *Ptr, Type *AccessTy, // We can value forward from an atomic to a non-atomic, but not the // other way around. - if (LI->isAtomic() < IsAtomicMemOp) + if (LI->isAtomic() < Load->isAtomic()) return nullptr; if (AATags) @@ -359,7 +369,7 @@ Value *llvm::FindAvailableLoadedValue(Value *Ptr, Type *AccessTy, // We can value forward from an atomic to a non-atomic, but not the // other way around. - if (SI->isAtomic() < IsAtomicMemOp) + if (SI->isAtomic() < Load->isAtomic()) return nullptr; if (AATags) @@ -403,24 +413,3 @@ Value *llvm::FindAvailableLoadedValue(Value *Ptr, Type *AccessTy, // block. return nullptr; } - - -Value *llvm::FindAvailableLoadedValue(LoadInst *Load, BasicBlock *ScanBB, - BasicBlock::iterator &ScanFrom, - unsigned MaxInstsToScan, - AliasAnalysis *AA, AAMDNodes *AATags, - bool *IsLoadCSE) { - - // We can never remove a volatile load - if (Load->isVolatile()) - return nullptr; - - // Anything stronger than unordered is currently unimplemented. - if (!Load->isUnordered()) - return nullptr; - - // Return the full value of the load if available. - return FindAvailableLoadedValue(Load->getPointerOperand(), Load->getType(), - Load->isAtomic(), ScanBB, ScanFrom, - MaxInstsToScan, AA, AATags, IsLoadCSE); -} diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp index 395e83661d5..20556157188 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -13,10 +13,9 @@ #include "InstCombineInternal.h" #include "llvm/Analysis/ConstantFolding.h" -#include "llvm/Analysis/Loads.h" -#include "llvm/Analysis/TargetLibraryInfo.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/PatternMatch.h" +#include "llvm/Analysis/TargetLibraryInfo.h" using namespace llvm; using namespace PatternMatch; @@ -576,27 +575,6 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) { if (Instruction *I = foldVecTruncToExtElt(CI, *this, DL)) return I; - // When trunc operand is a widened load, see if we can get the value from a - // previous store/load - if (auto *LI = dyn_cast<LoadInst>(Src)) { - BasicBlock::iterator BBI(*LI); - - // Scan a few instructions up from LI and if we find a partial load/store - // of Type DestTy that feeds into LI, we can replace all uses of the trunc - // with the load/store value. - // This replacement can be done only in the case of non-volatile loads, with - // ordering at most unordered. If the load is atomic, its only use should be - // the trunc instruction. We don't want to allow other users of LI to see a - // value that is out of sync with the value we're folding the trunc to (in - // case of a race). - if (LI->isUnordered() && (!LI->isAtomic() || LI->hasOneUse())) - if (Value *AvailableVal = FindAvailableLoadedValue( - LI->getPointerOperand(), DestTy, LI->isAtomic(), LI->getParent(), - BBI, DefMaxInstsToScan)) - return replaceInstUsesWith( - CI, Builder->CreateBitOrPointerCast(AvailableVal, CI.getType(), - CI.getName() + ".cast")); - } return nullptr; } |
