From 40107ce753ff172f76ceb67da2817868f952c003 Mon Sep 17 00:00:00 2001 From: Johannes Doerfert Date: Tue, 4 Jun 2019 20:21:46 +0000 Subject: [PATCH] Introduce Value::stripPointerCastsSameRepresentation This patch allows current users of Value::stripPointerCasts() to force the result of the function to have the same representation as the value it was called on. This is useful in various cases, e.g., (non-)null checks. In this patch only a single call site was adjusted to fix an existing misuse that would cause nonnull where they may be wrong. Uses in attribute deduction and other areas, e.g., D60047, are to be expected. For a discussion on this topic, please see [0]. [0] http://lists.llvm.org/pipermail/llvm-dev/2018-December/128423.html Reviewers: hfinkel, arsenm, reames Subscribers: wdng, hiraditya, bollu, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D61607 llvm-svn: 362545 --- clang/test/CodeGenOpenCLCXX/addrspace-references.cl | 2 +- llvm/include/llvm/IR/Value.h | 13 ++++++++++++- llvm/lib/Analysis/LazyValueInfo.cpp | 2 +- llvm/lib/IR/Value.cpp | 13 ++++++++++++- 4 files changed, 26 insertions(+), 4 deletions(-) diff --git a/clang/test/CodeGenOpenCLCXX/addrspace-references.cl b/clang/test/CodeGenOpenCLCXX/addrspace-references.cl index b17e701..19aeebe 100644 --- a/clang/test/CodeGenOpenCLCXX/addrspace-references.cl +++ b/clang/test/CodeGenOpenCLCXX/addrspace-references.cl @@ -9,6 +9,6 @@ void foo() { // CHECK: [[REF:%.*]] = alloca i32 // CHECK: store i32 1, i32* [[REF]] // CHECK: [[REG:%[0-9]+]] = addrspacecast i32* [[REF]] to i32 addrspace(4)* - // CHECK: call spir_func i32 @_Z3barRU3AS4Kj(i32 addrspace(4)* nonnull dereferenceable(4) [[REG]]) + // CHECK: call spir_func i32 @_Z3barRU3AS4Kj(i32 addrspace(4)* dereferenceable(4) [[REG]]) bar(1); } diff --git a/llvm/include/llvm/IR/Value.h b/llvm/include/llvm/IR/Value.h index d0de008..3f8caa6 100644 --- a/llvm/include/llvm/IR/Value.h +++ b/llvm/include/llvm/IR/Value.h @@ -493,7 +493,7 @@ public: /// swifterror attribute. bool isSwiftError() const; - /// Strip off pointer casts, all-zero GEPs, and aliases. + /// Strip off pointer casts, all-zero GEPs, address space casts, and aliases. /// /// Returns the original uncasted value. If this is called on a non-pointer /// value, it returns 'this'. @@ -503,6 +503,17 @@ public: static_cast(this)->stripPointerCasts()); } + /// Strip off pointer casts, all-zero GEPs, address space casts, and aliases + /// but ensures the representation of the result stays the same. + /// + /// Returns the original uncasted value with the same representation. If this + /// is called on a non-pointer value, it returns 'this'. + const Value *stripPointerCastsSameRepresentation() const; + Value *stripPointerCastsSameRepresentation() { + return const_cast(static_cast(this) + ->stripPointerCastsSameRepresentation()); + } + /// Strip off pointer casts, all-zero GEPs, aliases and invariant group /// info. /// diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp index 53e9f49a..542ff70 100644 --- a/llvm/lib/Analysis/LazyValueInfo.cpp +++ b/llvm/lib/Analysis/LazyValueInfo.cpp @@ -1803,7 +1803,7 @@ LazyValueInfo::getPredicateAt(unsigned Pred, Value *V, Constant *C, // through would still be correct. const DataLayout &DL = CxtI->getModule()->getDataLayout(); if (V->getType()->isPointerTy() && C->isNullValue() && - isKnownNonZero(V->stripPointerCasts(), DL)) { + isKnownNonZero(V->stripPointerCastsSameRepresentation(), DL)) { if (Pred == ICmpInst::ICMP_EQ) return LazyValueInfo::False; else if (Pred == ICmpInst::ICMP_NE) diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp index cf32a66..9e0a43c 100644 --- a/llvm/lib/IR/Value.cpp +++ b/llvm/lib/IR/Value.cpp @@ -460,6 +460,7 @@ namespace { enum PointerStripKind { PSK_ZeroIndices, PSK_ZeroIndicesAndAliases, + PSK_ZeroIndicesAndAliasesSameRepresentation, PSK_ZeroIndicesAndAliasesAndInvariantGroups, PSK_InBoundsConstantIndices, PSK_InBounds @@ -479,6 +480,7 @@ static const Value *stripPointerCastsAndOffsets(const Value *V) { if (auto *GEP = dyn_cast(V)) { switch (StripKind) { case PSK_ZeroIndicesAndAliases: + case PSK_ZeroIndicesAndAliasesSameRepresentation: case PSK_ZeroIndicesAndAliasesAndInvariantGroups: case PSK_ZeroIndices: if (!GEP->hasAllZeroIndices()) @@ -494,8 +496,12 @@ static const Value *stripPointerCastsAndOffsets(const Value *V) { break; } V = GEP->getPointerOperand(); - } else if (Operator::getOpcode(V) == Instruction::BitCast || + } else if (Operator::getOpcode(V) == Instruction::BitCast) { + V = cast(V)->getOperand(0); + } else if (StripKind != PSK_ZeroIndicesAndAliasesSameRepresentation && Operator::getOpcode(V) == Instruction::AddrSpaceCast) { + // TODO: If we know an address space cast will not change the + // representation we could look through it here as well. V = cast(V)->getOperand(0); } else if (auto *GA = dyn_cast(V)) { if (StripKind == PSK_ZeroIndices || GA->isInterposable()) @@ -530,6 +536,11 @@ const Value *Value::stripPointerCasts() const { return stripPointerCastsAndOffsets(this); } +const Value *Value::stripPointerCastsSameRepresentation() const { + return stripPointerCastsAndOffsets< + PSK_ZeroIndicesAndAliasesSameRepresentation>(this); +} + const Value *Value::stripPointerCastsNoFollowAliases() const { return stripPointerCastsAndOffsets(this); } -- 2.7.4