diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp | 39 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/trunc-load.ll | 62 |
2 files changed, 12 insertions, 89 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp index 08a7a068af2..2c9ba203fbf 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -681,42 +681,6 @@ static Instruction *shrinkInsertElt(CastInst &Trunc, return nullptr; } -static Instruction *narrowLoad(TruncInst &Trunc, - InstCombiner::BuilderTy &Builder, - const DataLayout &DL) { - // Check the layout to ensure we are not creating an unsupported operation. - // TODO: Create a GEP to offset the load? - if (!DL.isLittleEndian()) - return nullptr; - unsigned NarrowBitWidth = Trunc.getDestTy()->getPrimitiveSizeInBits(); - if (!DL.isLegalInteger(NarrowBitWidth)) - return nullptr; - - // Match a truncated load with no other uses. - Value *X; - if (!match(Trunc.getOperand(0), m_OneUse(m_Load(m_Value(X))))) - return nullptr; - LoadInst *WideLoad = cast<LoadInst>(Trunc.getOperand(0)); - if (!WideLoad->isSimple()) - return nullptr; - - // Don't narrow this load if we would lose information about the - // dereferenceable range. - bool CanBeNull; - uint64_t DerefBits = X->getPointerDereferenceableBytes(DL, CanBeNull) * 8; - if (DerefBits < WideLoad->getType()->getPrimitiveSizeInBits()) - return nullptr; - - // trunc (load X) --> load (bitcast X) - PointerType *PtrTy = PointerType::get(Trunc.getDestTy(), - WideLoad->getPointerAddressSpace()); - Value *Bitcast = Builder.CreatePointerCast(X, PtrTy); - LoadInst *NarrowLoad = new LoadInst(Trunc.getDestTy(), Bitcast); - NarrowLoad->setAlignment(WideLoad->getAlignment()); - copyMetadataForLoad(*NarrowLoad, *WideLoad); - return NarrowLoad; -} - Instruction *InstCombiner::visitTrunc(TruncInst &CI) { if (Instruction *Result = commonCastTransforms(CI)) return Result; @@ -876,9 +840,6 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) { if (Instruction *I = foldVecTruncToExtElt(CI, *this)) return I; - if (Instruction *NewLoad = narrowLoad(CI, Builder, DL)) - return NewLoad; - return nullptr; } diff --git a/llvm/test/Transforms/InstCombine/trunc-load.ll b/llvm/test/Transforms/InstCombine/trunc-load.ll index c85c035da86..e17e99b1338 100644 --- a/llvm/test/Transforms/InstCombine/trunc-load.ll +++ b/llvm/test/Transforms/InstCombine/trunc-load.ll @@ -29,15 +29,10 @@ define i32 @truncload_small_deref(i64* dereferenceable(7) %ptr) { ; On little-endian, we can narrow the load without an offset. define i32 @truncload_deref(i64* dereferenceable(8) %ptr) { -; LE-LABEL: @truncload_deref( -; LE-NEXT: [[TMP1:%.*]] = bitcast i64* [[PTR:%.*]] to i32* -; LE-NEXT: [[R:%.*]] = load i32, i32* [[TMP1]], align 4 -; LE-NEXT: ret i32 [[R]] -; -; BE-LABEL: @truncload_deref( -; BE-NEXT: [[X:%.*]] = load i64, i64* [[PTR:%.*]], align 4 -; BE-NEXT: [[R:%.*]] = trunc i64 [[X]] to i32 -; BE-NEXT: ret i32 [[R]] +; CHECK-LABEL: @truncload_deref( +; CHECK-NEXT: [[X:%.*]] = load i64, i64* [[PTR:%.*]], align 4 +; CHECK-NEXT: [[R:%.*]] = trunc i64 [[X]] to i32 +; CHECK-NEXT: ret i32 [[R]] ; %x = load i64, i64* %ptr %r = trunc i64 %x to i32 @@ -47,15 +42,10 @@ define i32 @truncload_deref(i64* dereferenceable(8) %ptr) { ; Preserve alignment. define i16 @truncload_align(i32* dereferenceable(14) %ptr) { -; LE-LABEL: @truncload_align( -; LE-NEXT: [[TMP1:%.*]] = bitcast i32* [[PTR:%.*]] to i16* -; LE-NEXT: [[R:%.*]] = load i16, i16* [[TMP1]], align 16 -; LE-NEXT: ret i16 [[R]] -; -; BE-LABEL: @truncload_align( -; BE-NEXT: [[X:%.*]] = load i32, i32* [[PTR:%.*]], align 16 -; BE-NEXT: [[R:%.*]] = trunc i32 [[X]] to i16 -; BE-NEXT: ret i16 [[R]] +; CHECK-LABEL: @truncload_align( +; CHECK-NEXT: [[X:%.*]] = load i32, i32* [[PTR:%.*]], align 16 +; CHECK-NEXT: [[R:%.*]] = trunc i32 [[X]] to i16 +; CHECK-NEXT: ret i16 [[R]] ; %x = load i32, i32* %ptr, align 16 %r = trunc i32 %x to i16 @@ -108,40 +98,12 @@ define i32 @truncload_volatile(i64* dereferenceable(8) %ptr) { ; Preserve address space. define i32 @truncload_address_space(i64 addrspace(1)* dereferenceable(8) %ptr) { -; LE-LABEL: @truncload_address_space( -; LE-NEXT: [[TMP1:%.*]] = bitcast i64 addrspace(1)* [[PTR:%.*]] to i32 addrspace(1)* -; LE-NEXT: [[R:%.*]] = load i32, i32 addrspace(1)* [[TMP1]], align 4 -; LE-NEXT: ret i32 [[R]] -; -; BE-LABEL: @truncload_address_space( -; BE-NEXT: [[X:%.*]] = load i64, i64 addrspace(1)* [[PTR:%.*]], align 4 -; BE-NEXT: [[R:%.*]] = trunc i64 [[X]] to i32 -; BE-NEXT: ret i32 [[R]] +; CHECK-LABEL: @truncload_address_space( +; CHECK-NEXT: [[X:%.*]] = load i64, i64 addrspace(1)* [[PTR:%.*]], align 4 +; CHECK-NEXT: [[R:%.*]] = trunc i64 [[X]] to i32 +; CHECK-NEXT: ret i32 [[R]] ; %x = load i64, i64 addrspace(1)* %ptr, align 4 %r = trunc i64 %x to i32 ret i32 %r } - -; Most metadata should be transferred to the narrow load. -; TODO: We lost the range. - -define i32 @truncload_metadata(i64* dereferenceable(8) %ptr) { -; LE-LABEL: @truncload_metadata( -; LE-NEXT: [[TMP1:%.*]] = bitcast i64* [[PTR:%.*]] to i32* -; LE-NEXT: [[R:%.*]] = load i32, i32* [[TMP1]], align 4, !invariant.load !0, !nontemporal !1 -; LE-NEXT: ret i32 [[R]] -; -; BE-LABEL: @truncload_metadata( -; BE-NEXT: [[X:%.*]] = load i64, i64* [[PTR:%.*]], align 4, !range !0, !invariant.load !1, !nontemporal !2 -; BE-NEXT: [[R:%.*]] = trunc i64 [[X]] to i32 -; BE-NEXT: ret i32 [[R]] -; - %x = load i64, i64* %ptr, align 4, !invariant.load !0, !nontemporal !1, !range !2 - %r = trunc i64 %x to i32 - ret i32 %r -} - -!0 = !{} -!1 = !{i32 1} -!2 = !{i64 0, i64 2} |
