diff options
| -rw-r--r-- | llvm/lib/Transforms/Utils/VNCoercion.cpp | 10 | ||||
| -rw-r--r-- | llvm/test/Transforms/GVN/non-integral-pointers.ll | 24 |
2 files changed, 24 insertions, 10 deletions
diff --git a/llvm/lib/Transforms/Utils/VNCoercion.cpp b/llvm/lib/Transforms/Utils/VNCoercion.cpp index 181e53e7605..19593054c23 100644 --- a/llvm/lib/Transforms/Utils/VNCoercion.cpp +++ b/llvm/lib/Transforms/Utils/VNCoercion.cpp @@ -36,8 +36,8 @@ bool canCoerceMustAliasedValueToLoad(Value *StoredVal, Type *LoadTy, // As a special case, allow coercion of memset used to initialize // an array w/null. Despite non-integral pointers not generally having a // specific bit pattern, we do assume null is zero. - if (auto *CI = dyn_cast<ConstantInt>(StoredVal)) - return CI->isZero(); + if (auto *CI = dyn_cast<Constant>(StoredVal)) + return CI->isNullValue(); return false; } @@ -287,9 +287,8 @@ int analyzeLoadFromClobberingMemInst(Type *LoadTy, Value *LoadPtr, // If this is memset, we just need to see if the offset is valid in the size // of the memset.. if (MI->getIntrinsicID() == Intrinsic::memset) { - Value *StoredVal = cast<MemSetInst>(MI)->getValue(); if (DL.isNonIntegralPointerType(LoadTy->getScalarType())) { - auto *CI = dyn_cast<ConstantInt>(StoredVal); + auto *CI = dyn_cast<ConstantInt>(cast<MemSetInst>(MI)->getValue()); if (!CI || !CI->isZero()) return -1; } @@ -316,7 +315,8 @@ int analyzeLoadFromClobberingMemInst(Type *LoadTy, Value *LoadPtr, if (Offset == -1) return Offset; - // Don't coerce non-integral pointers to integers or vice versa. + // Don't coerce non-integral pointers to integers or vice versa, and the + // memtransfer is implicitly a raw byte code if (DL.isNonIntegralPointerType(LoadTy->getScalarType())) // TODO: Can allow nullptrs from constant zeros return -1; diff --git a/llvm/test/Transforms/GVN/non-integral-pointers.ll b/llvm/test/Transforms/GVN/non-integral-pointers.ll index 7c260639185..254defe0690 100644 --- a/llvm/test/Transforms/GVN/non-integral-pointers.ll +++ b/llvm/test/Transforms/GVN/non-integral-pointers.ll @@ -139,18 +139,32 @@ define <1 x i8 addrspace(4)*> @neg_forward_store_vload(<1 x i8 addrspace(4)*> ad ret <1 x i8 addrspace(4)*> %ref } -; TODO: missed optimization, we can forward the null. +; Nulls have known bit patterns, so we can forward define i8 addrspace(4)* @forward_store_zero(i8 addrspace(4)* addrspace(4)* %loc) { ; CHECK-LABEL: @forward_store_zero( ; CHECK-NEXT: entry: ; CHECK-NEXT: [[LOC_BC:%.*]] = bitcast i8 addrspace(4)* addrspace(4)* [[LOC:%.*]] to i64 addrspace(4)* -; CHECK-NEXT: store i64 5, i64 addrspace(4)* [[LOC_BC]] -; CHECK-NEXT: [[REF:%.*]] = load i8 addrspace(4)*, i8 addrspace(4)* addrspace(4)* [[LOC]] -; CHECK-NEXT: ret i8 addrspace(4)* [[REF]] +; CHECK-NEXT: store i64 0, i64 addrspace(4)* [[LOC_BC]] +; CHECK-NEXT: ret i8 addrspace(4)* null ; entry: %loc.bc = bitcast i8 addrspace(4)* addrspace(4)* %loc to i64 addrspace(4)* - store i64 5, i64 addrspace(4)* %loc.bc + store i64 0, i64 addrspace(4)* %loc.bc + %ref = load i8 addrspace(4)*, i8 addrspace(4)* addrspace(4)* %loc + ret i8 addrspace(4)* %ref +} + +; Nulls have known bit patterns, so we can forward +define i8 addrspace(4)* @forward_store_zero2(i8 addrspace(4)* addrspace(4)* %loc) { +; CHECK-LABEL: @forward_store_zero2( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[LOC_BC:%.*]] = bitcast i8 addrspace(4)* addrspace(4)* [[LOC:%.*]] to <2 x i32> addrspace(4)* +; CHECK-NEXT: store <2 x i32> zeroinitializer, <2 x i32> addrspace(4)* [[LOC_BC]] +; CHECK-NEXT: ret i8 addrspace(4)* null +; + entry: + %loc.bc = bitcast i8 addrspace(4)* addrspace(4)* %loc to <2 x i32> addrspace(4)* + store <2 x i32> zeroinitializer, <2 x i32> addrspace(4)* %loc.bc %ref = load i8 addrspace(4)*, i8 addrspace(4)* addrspace(4)* %loc ret i8 addrspace(4)* %ref } |
