diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -17780,6 +17780,13 @@ EVT ResultVT = EVE->getValueType(0); EVT VecEltVT = InVecVT.getVectorElementType(); + + // If the vector element type is not a multiple of a byte then we are unable + // to correctly compute an address to load only the extracted element as a + // scalar. + if (!VecEltVT.isByteSized()) + return SDValue(); + Align Alignment = OriginalLoad->getAlign(); Align NewAlign = DAG.getDataLayout().getABITypeAlign( VecEltVT.getTypeForEVT(*DAG.getContext())); diff --git a/llvm/test/CodeGen/AMDGPU/extract-load-i1.ll b/llvm/test/CodeGen/AMDGPU/extract-load-i1.ll --- a/llvm/test/CodeGen/AMDGPU/extract-load-i1.ll +++ b/llvm/test/CodeGen/AMDGPU/extract-load-i1.ll @@ -1,16 +1,34 @@ ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py ; RUN: llc -mtriple=amdgcn-amd-amdhsa < %s | FileCheck %s -; FIXME: Incorrect codegen during an optimization of load + extractelement when -; the vector element type is not byte-sized: this test loads from %idx-many -; bytes from address %ptr, instead of that many bits. +; FIXME: Inefficient codegen which skips an optimization of load + +; extractelement when the vector element type is not byte-sized. define i1 @extractloadi1(<8 x i1> *%ptr, i32 %idx) { ; CHECK-LABEL: extractloadi1: ; CHECK: ; %bb.0: ; CHECK-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) -; CHECK-NEXT: v_mad_u64_u32 v[0:1], s[4:5], v2, 1, v[0:1] ; CHECK-NEXT: flat_load_ubyte v0, v[0:1] +; CHECK-NEXT: v_and_b32_e32 v1, 7, v2 +; CHECK-NEXT: v_lshr_b32_e64 v9, s32, 6 +; CHECK-NEXT: v_or_b32_e32 v1, v9, v1 ; CHECK-NEXT: s_waitcnt vmcnt(0) lgkmcnt(0) +; CHECK-NEXT: v_bfe_u32 v2, v0, 1, 1 +; CHECK-NEXT: v_bfe_u32 v3, v0, 2, 2 +; CHECK-NEXT: v_bfe_u32 v4, v0, 3, 1 +; CHECK-NEXT: v_lshrrev_b32_e32 v5, 4, v0 +; CHECK-NEXT: v_bfe_u32 v6, v0, 5, 1 +; CHECK-NEXT: v_lshrrev_b32_e32 v7, 6, v0 +; CHECK-NEXT: v_lshrrev_b32_e32 v8, 7, v0 +; CHECK-NEXT: buffer_store_byte v0, off, s[0:3], s32 +; CHECK-NEXT: buffer_store_byte v8, off, s[0:3], s32 offset:7 +; CHECK-NEXT: buffer_store_byte v7, off, s[0:3], s32 offset:6 +; CHECK-NEXT: buffer_store_byte v6, off, s[0:3], s32 offset:5 +; CHECK-NEXT: buffer_store_byte v5, off, s[0:3], s32 offset:4 +; CHECK-NEXT: buffer_store_byte v4, off, s[0:3], s32 offset:3 +; CHECK-NEXT: buffer_store_byte v3, off, s[0:3], s32 offset:2 +; CHECK-NEXT: buffer_store_byte v2, off, s[0:3], s32 offset:1 +; CHECK-NEXT: buffer_load_ubyte v0, v1, s[0:3], 0 offen +; CHECK-NEXT: s_waitcnt vmcnt(0) ; CHECK-NEXT: s_setpc_b64 s[30:31] %val = load <8 x i1>, <8 x i1> *%ptr %ret = extractelement <8 x i1> %val, i32 %idx