diff options
Diffstat (limited to 'llvm/lib/Analysis/LoopAccessAnalysis.cpp')
| -rw-r--r-- | llvm/lib/Analysis/LoopAccessAnalysis.cpp | 59 |
1 files changed, 20 insertions, 39 deletions
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp index 43380b5..7d6dbd5 100644 --- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp +++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp @@ -793,26 +793,6 @@ private: } // end anonymous namespace -/// Check whether a pointer can participate in a runtime bounds check. -/// If \p Assume, try harder to prove that we can compute the bounds of \p Ptr -/// by adding run-time checks (overflow checks) if necessary. -static bool hasComputableBounds(PredicatedScalarEvolution &PSE, Value *Ptr, - const SCEV *PtrScev, Loop *L, bool Assume) { - // The bounds for loop-invariant pointer is trivial. - if (PSE.getSE()->isLoopInvariant(PtrScev, L)) - return true; - - const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PtrScev); - - if (!AR && Assume) - AR = PSE.getAsAddRec(Ptr); - - if (!AR) - return false; - - return AR->isAffine(); -} - /// Try to compute the stride for \p AR. Used by getPtrStride. static std::optional<int64_t> getStrideFromAddRec(const SCEVAddRecExpr *AR, const Loop *Lp, Type *AccessTy, @@ -859,21 +839,9 @@ static bool isNoWrapAddRec(Value *Ptr, const SCEVAddRecExpr *AR, PredicatedScalarEvolution &PSE, const Loop *L); /// Check whether a pointer address cannot wrap. -static bool isNoWrap(PredicatedScalarEvolution &PSE, - const DenseMap<Value *, const SCEV *> &Strides, Value *Ptr, - Type *AccessTy, const Loop *L, bool Assume, +static bool isNoWrap(PredicatedScalarEvolution &PSE, const SCEVAddRecExpr *AR, + Value *Ptr, Type *AccessTy, const Loop *L, bool Assume, std::optional<int64_t> Stride = std::nullopt) { - const SCEV *PtrScev = replaceSymbolicStrideSCEV(PSE, Strides, Ptr); - if (PSE.getSE()->isLoopInvariant(PtrScev, L)) - return true; - - const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PtrScev); - if (!AR) { - if (!Assume) - return false; - AR = PSE.getAsAddRec(Ptr); - } - // The address calculation must not wrap. Otherwise, a dependence could be // inverted. if (isNoWrapAddRec(Ptr, AR, PSE, L)) @@ -1143,14 +1111,27 @@ bool AccessAnalysis::createCheckForAccess(RuntimePointerChecking &RtCheck, SmallVector<PointerIntPair<const SCEV *, 1, bool>> TranslatedPtrs = findForkedPointer(PSE, StridesMap, Ptr, TheLoop); + /// Check whether all pointers can participate in a runtime bounds check. They + /// must either be invariant or AddRecs. If ShouldCheckWrap is true, they also + /// must not wrap. for (auto &P : TranslatedPtrs) { - if (!hasComputableBounds(PSE, Ptr, P.getPointer(), TheLoop, Assume)) + // The bounds for loop-invariant pointer is trivial. + if (PSE.getSE()->isLoopInvariant(P.getPointer(), TheLoop)) + continue; + + const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(P.getPointer()); + if (!AR && Assume) + AR = PSE.getAsAddRec(Ptr); + if (!AR || !AR->isAffine()) return false; // If there's only one option for Ptr, look it up after bounds and wrap // checking, because assumptions might have been added to PSE. - if (TranslatedPtrs.size() == 1) - P.setPointer(replaceSymbolicStrideSCEV(PSE, StridesMap, Ptr)); + if (TranslatedPtrs.size() == 1) { + AR = + cast<SCEVAddRecExpr>(replaceSymbolicStrideSCEV(PSE, StridesMap, Ptr)); + P.setPointer(AR); + } // When we run after a failing dependency check we have to make sure // we don't have wrapping pointers. @@ -1159,7 +1140,7 @@ bool AccessAnalysis::createCheckForAccess(RuntimePointerChecking &RtCheck, if (TranslatedPtrs.size() > 1) return false; - if (!isNoWrap(PSE, StridesMap, Ptr, AccessTy, TheLoop, Assume)) + if (!isNoWrap(PSE, AR, Ptr, AccessTy, TheLoop, Assume)) return false; } } @@ -1548,7 +1529,7 @@ llvm::getPtrStride(PredicatedScalarEvolution &PSE, Type *AccessTy, Value *Ptr, if (!ShouldCheckWrap || !Stride) return Stride; - if (isNoWrap(PSE, StridesMap, Ptr, AccessTy, Lp, Assume, Stride)) + if (isNoWrap(PSE, AR, Ptr, AccessTy, Lp, Assume, Stride)) return Stride; LLVM_DEBUG( |