From: Eli Friedman Date: Mon, 28 Nov 2011 22:48:22 +0000 (+0000) Subject: Make SelectionDAG::InferPtrAlignment use llvm::ComputeMaskedBits instead of duplicati... X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=c4c2a024857ca92687728f573a3017091a79eaf4 Make SelectionDAG::InferPtrAlignment use llvm::ComputeMaskedBits instead of duplicating the logic for globals. Make llvm::ComputeMaskedBits handle GlobalVariables slightly more aggressively, to match what InferPtrAlignment knew how to do. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145304 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 22f1c144ea2..8192c1471fc 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -103,14 +103,16 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, if (GlobalValue *GV = dyn_cast(V)) { unsigned Align = GV->getAlignment(); if (Align == 0 && TD && GV->getType()->getElementType()->isSized()) { - Type *ObjectType = GV->getType()->getElementType(); - // If the object is defined in the current Module, we'll be giving - // it the preferred alignment. Otherwise, we have to assume that it - // may only have the minimum ABI alignment. - if (!GV->isDeclaration() && !GV->mayBeOverridden()) - Align = TD->getPrefTypeAlignment(ObjectType); - else - Align = TD->getABITypeAlignment(ObjectType); + if (GlobalVariable *GVar = dyn_cast(GV)) { + Type *ObjectType = GVar->getType()->getElementType(); + // If the object is defined in the current Module, we'll be giving + // it the preferred alignment. Otherwise, we have to assume that it + // may only have the minimum ABI alignment. + if (!GVar->isDeclaration() && !GVar->mayBeOverridden()) + Align = TD->getPreferredAlignment(GVar); + else + Align = TD->getABITypeAlignment(ObjectType); + } } if (Align > 0) KnownZero = Mask & APInt::getLowBitsSet(BitWidth, diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 024a1637371..aa06955689e 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -6553,24 +6553,15 @@ unsigned SelectionDAG::InferPtrAlignment(SDValue Ptr) const { const GlobalValue *GV; int64_t GVOffset = 0; if (TLI.isGAPlusOffset(Ptr.getNode(), GV, GVOffset)) { - // If GV has specified alignment, then use it. Otherwise, use the preferred - // alignment. - unsigned Align = GV->getAlignment(); - if (!Align) { - if (const GlobalVariable *GVar = dyn_cast(GV)) { - if (GVar->hasInitializer()) { - const TargetData *TD = TLI.getTargetData(); - Align = TD->getPreferredAlignment(GVar); - } - } - if (!Align) - // Conservatively returns zero here instead of using ABI alignment for - // type of the GV. If the type is a "packed" type, then the under- - // specified alignments is attached to the load / store instructions. - // In that case, the alignment of the type cannot be trusted. - return 0; - } - return MinAlign(Align, GVOffset); + unsigned PtrWidth = TLI.getPointerTy().getSizeInBits(); + APInt AllOnes = APInt::getAllOnesValue(PtrWidth); + APInt KnownZero(PtrWidth, 0), KnownOne(PtrWidth, 0); + llvm::ComputeMaskedBits(const_cast(GV), AllOnes, + KnownZero, KnownOne, TLI.getTargetData()); + unsigned AlignBits = KnownZero.countTrailingOnes(); + unsigned Align = AlignBits ? 1 << std::min(31U, AlignBits) : 0; + if (Align) + return MinAlign(Align, GVOffset); } // If this is a direct reference to a stack slot, use information about the diff --git a/test/Transforms/InstCombine/constant-fold-gep.ll b/test/Transforms/InstCombine/constant-fold-gep.ll index c679226d4a9..e5b16ea0ffd 100644 --- a/test/Transforms/InstCombine/constant-fold-gep.ll +++ b/test/Transforms/InstCombine/constant-fold-gep.ll @@ -9,7 +9,7 @@ target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f3 @Y = internal global [3 x %struct.X] zeroinitializer define void @frob() { -; CHECK: store i32 1, i32* getelementptr inbounds ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 0), align 8 +; CHECK: store i32 1, i32* getelementptr inbounds ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 0), align 16 store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 0), align 4 ; CHECK: store i32 1, i32* getelementptr inbounds ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 1), align 4 store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 1), align 4 @@ -33,7 +33,7 @@ define void @frob() { store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 10), align 4 ; CHECK: store i32 1, i32* getelementptr inbounds ([3 x %struct.X]* @Y, i64 0, i64 1, i32 1, i64 2), align 4 store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 11), align 4 -; CHECK: store i32 1, i32* getelementptr inbounds ([3 x %struct.X]* @Y, i64 0, i64 2, i32 0, i64 0), align 8 +; CHECK: store i32 1, i32* getelementptr inbounds ([3 x %struct.X]* @Y, i64 0, i64 2, i32 0, i64 0), align 16 store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 12), align 4 ; CHECK: store i32 1, i32* getelementptr inbounds ([3 x %struct.X]* @Y, i64 0, i64 2, i32 0, i64 1), align 4 store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 13), align 4 @@ -47,7 +47,7 @@ define void @frob() { store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 17), align 8 ; CHECK: store i32 1, i32* getelementptr inbounds ([3 x %struct.X]* @Y, i64 1, i64 0, i32 0, i64 0), align 8 store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 18), align 8 -; CHECK: store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 2, i64 0, i32 0, i64 0), align 8 +; CHECK: store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 2, i64 0, i32 0, i64 0), align 16 store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 36), align 8 ; CHECK: store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 1, i64 0, i32 0, i64 1), align 8 store i32 1, i32* getelementptr ([3 x %struct.X]* @Y, i64 0, i64 0, i32 0, i64 19), align 8