Author: hans Date: Fri Aug 31 08:53:05 2018 New Revision: 341220 URL: http://llvm.org/viewvc/llvm-project?rev=341220&view=rev Log: Merging r341094: ------------------------------------------------------------------------ r341094 | efriedma | 2018-08-30 20:59:24 +0200 (Thu, 30 Aug 2018) | 11 lines
[SROA] Fix alignment for uses of PHI nodes. Splitting an alloca can decrease the alignment of GEPs into the partition. Normally, rewriting accounts for this, but the code was missing for uses of PHI nodes and select instructions. Fixes https://bugs.llvm.org/show_bug.cgi?id=38707 . Differential Revision: https://reviews.llvm.org/D51335 ------------------------------------------------------------------------ Modified: llvm/branches/release_70/ (props changed) llvm/branches/release_70/lib/Transforms/Scalar/SROA.cpp llvm/branches/release_70/test/Transforms/SROA/phi-and-select.ll Propchange: llvm/branches/release_70/ ------------------------------------------------------------------------------ --- svn:mergeinfo (original) +++ svn:mergeinfo Fri Aug 31 08:53:05 2018 @@ -1,3 +1,3 @@ /llvm/branches/Apple/Pertwee:110850,110961 /llvm/branches/type-system-rewrite:133420-134817 -/llvm/trunk:155241,338552,338554,338569,338599,338610,338658,338665,338682,338703,338709,338716,338751,338762,338817,338841,338902,338915,338968,339073,339091,339166,339179,339184,339190,339225,339316,339319,339411,339492,339515,339533,339535-339536,339600,339636,339674,339769,339822,339883,339895-339896,339945,340158,340303,340416-340417,340455,340641,340691,340751,340820,340839,340900 +/llvm/trunk:155241,338552,338554,338569,338599,338610,338658,338665,338682,338703,338709,338716,338751,338762,338817,338841,338902,338915,338968,339073,339091,339166,339179,339184,339190,339225,339316,339319,339411,339492,339515,339533,339535-339536,339600,339636,339674,339769,339822,339883,339895-339896,339945,340158,340303,340416-340417,340455,340641,340691,340751,340820,340839,340900,341094 Modified: llvm/branches/release_70/lib/Transforms/Scalar/SROA.cpp URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_70/lib/Transforms/Scalar/SROA.cpp?rev=341220&r1=341219&r2=341220&view=diff ============================================================================== --- llvm/branches/release_70/lib/Transforms/Scalar/SROA.cpp (original) +++ llvm/branches/release_70/lib/Transforms/Scalar/SROA.cpp Fri Aug 31 08:53:05 2018 @@ -3046,6 +3046,42 @@ private: return true; } + void fixLoadStoreAlign(Instruction &Root) { + // This algorithm implements the same visitor loop as + // hasUnsafePHIOrSelectUse, and fixes the alignment of each load + // or store found. + SmallPtrSet<Instruction *, 4> Visited; + SmallVector<Instruction *, 4> Uses; + Visited.insert(&Root); + Uses.push_back(&Root); + do { + Instruction *I = Uses.pop_back_val(); + + if (LoadInst *LI = dyn_cast<LoadInst>(I)) { + unsigned LoadAlign = LI->getAlignment(); + if (!LoadAlign) + LoadAlign = DL.getABITypeAlignment(LI->getType()); + LI->setAlignment(std::min(LoadAlign, getSliceAlign())); + continue; + } + if (StoreInst *SI = dyn_cast<StoreInst>(I)) { + unsigned StoreAlign = SI->getAlignment(); + if (!StoreAlign) { + Value *Op = SI->getOperand(0); + StoreAlign = DL.getABITypeAlignment(Op->getType()); + } + SI->setAlignment(std::min(StoreAlign, getSliceAlign())); + continue; + } + + assert(isa<BitCastInst>(I) || isa<PHINode>(I) || + isa<SelectInst>(I) || isa<GetElementPtrInst>(I)); + for (User *U : I->users()) + if (Visited.insert(cast<Instruction>(U)).second) + Uses.push_back(cast<Instruction>(U)); + } while (!Uses.empty()); + } + bool visitPHINode(PHINode &PN) { LLVM_DEBUG(dbgs() << " original: " << PN << "\n"); assert(BeginOffset >= NewAllocaBeginOffset && "PHIs are unsplittable"); @@ -3069,6 +3105,9 @@ private: LLVM_DEBUG(dbgs() << " to: " << PN << "\n"); deleteIfTriviallyDead(OldPtr); + // Fix the alignment of any loads or stores using this PHI node. + fixLoadStoreAlign(PN); + // PHIs can't be promoted on their own, but often can be speculated. We // check the speculation outside of the rewriter so that we see the // fully-rewritten alloca. @@ -3093,6 +3132,9 @@ private: LLVM_DEBUG(dbgs() << " to: " << SI << "\n"); deleteIfTriviallyDead(OldPtr); + // Fix the alignment of any loads or stores using this select. + fixLoadStoreAlign(SI); + // Selects can't be promoted on their own, but often can be speculated. We // check the speculation outside of the rewriter so that we see the // fully-rewritten alloca. Modified: llvm/branches/release_70/test/Transforms/SROA/phi-and-select.ll URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_70/test/Transforms/SROA/phi-and-select.ll?rev=341220&r1=341219&r2=341220&view=diff ============================================================================== --- llvm/branches/release_70/test/Transforms/SROA/phi-and-select.ll (original) +++ llvm/branches/release_70/test/Transforms/SROA/phi-and-select.ll Fri Aug 31 08:53:05 2018 @@ -600,3 +600,35 @@ if.then5: store %struct.S undef, %struct.S* %f1, align 4 ret void } + +define i32 @phi_align(i32* %z) { +; CHECK-LABEL: @phi_align( +entry: + %a = alloca [8 x i8], align 8 +; CHECK: alloca [7 x i8] + + %a0x = getelementptr [8 x i8], [8 x i8]* %a, i64 0, i32 1 + %a0 = bitcast i8* %a0x to i32* + %a1x = getelementptr [8 x i8], [8 x i8]* %a, i64 0, i32 4 + %a1 = bitcast i8* %a1x to i32* +; CHECK: store i32 0, {{.*}}, align 1 + store i32 0, i32* %a0, align 1 +; CHECK: store i32 1, {{.*}}, align 1 + store i32 1, i32* %a1, align 4 +; CHECK: load {{.*}}, align 1 + %v0 = load i32, i32* %a0, align 1 +; CHECK: load {{.*}}, align 1 + %v1 = load i32, i32* %a1, align 4 + %cond = icmp sle i32 %v0, %v1 + br i1 %cond, label %then, label %exit + +then: + br label %exit + +exit: +; CHECK: %phi = phi i32* [ {{.*}}, %then ], [ %z, %entry ] +; CHECK-NEXT: %result = load i32, i32* %phi, align 1 + %phi = phi i32* [ %a1, %then ], [ %z, %entry ] + %result = load i32, i32* %phi, align 4 + ret i32 %result +} _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
