Index: llvm/lib/Analysis/InstructionSimplify.cpp =================================================================== --- llvm/lib/Analysis/InstructionSimplify.cpp +++ llvm/lib/Analysis/InstructionSimplify.cpp @@ -6586,6 +6586,12 @@ if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer()) return nullptr; + // If GlobalVariable's initializer is uniform, then return the constant + // regardless of its offset. + if (Constant *C = + ConstantFoldLoadFromUniformValue(GV->getInitializer(), LI->getType())) + return C; + // Try to convert operand into a constant by stripping offsets while looking // through invariant.group intrinsics. APInt Offset(Q.DL.getIndexTypeSizeInBits(PtrOp->getType()), 0); Index: llvm/test/Transforms/InstSimplify/load.ll =================================================================== --- llvm/test/Transforms/InstSimplify/load.ll +++ llvm/test/Transforms/InstSimplify/load.ll @@ -4,6 +4,12 @@ @zeroinit = constant {} zeroinitializer @poison = constant {} poison + +@constzeroarray = internal constant [4 x i32] zeroinitializer + +@constarray = internal constant [4 x i32] [i32 1, i32 1, i32 1, i32 1] +@constarrayi8 = internal constant [2 x i8] [i8 1, i8 1] + define i32 @crash_on_zeroinit() { ; CHECK-LABEL: @crash_on_zeroinit( ; CHECK-NEXT: ret i32 poison @@ -40,3 +46,46 @@ %1 = load <3 x float>, ptr getelementptr inbounds (<3 x float>, ptr @constvec, i64 1) ret <3 x float> %1 } + +define i32 @load_gep_const_zero_array(i64 %idx) { +; CHECK-LABEL: @load_gep_const_zero_array( +; CHECK-NEXT: ret i32 0 +; + %gep = getelementptr inbounds [4 x i32], ptr @constzeroarray, i64 0, i64 %idx + %load = load i32, ptr %gep + ret i32 %load +} + +define i8 @load_i8_multi_gep_const_zero_array(i64 %idx1, i64 %idx2) { +; CHECK-LABEL: @load_i8_multi_gep_const_zero_array( +; CHECK-NEXT: ret i8 0 +; + %gep1 = getelementptr inbounds i8, ptr @constzeroarray, i64 %idx1 + %gep = getelementptr inbounds i8, ptr %gep1, i64 %idx2 + %load = load i8, ptr %gep + ret i8 %load +} + +define i32 @load_gep_const_array(i64 %idx) { +; CHECK-LABEL: @load_gep_const_array( +; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds [4 x i32], ptr @constarray, i64 0, i64 [[IDX:%.*]] +; CHECK-NEXT: [[LOAD:%.*]] = load i32, ptr [[GEP]], align 4 +; CHECK-NEXT: ret i32 [[LOAD]] +; + %gep = getelementptr inbounds [4 x i32], ptr @constarray, i64 0, i64 %idx + %load = load i32, ptr %gep + ret i32 %load +} + +define i8 @load_i8_multi_gep_const_array(i64 %idx1, i64 %idx2) { +; CHECK-LABEL: @load_i8_multi_gep_const_array( +; CHECK-NEXT: [[GEP1:%.*]] = getelementptr inbounds i8, ptr @constarrayi8, i64 [[IDX1:%.*]] +; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, ptr [[GEP1]], i64 [[IDX2:%.*]] +; CHECK-NEXT: [[LOAD:%.*]] = load i8, ptr [[GEP]], align 1 +; CHECK-NEXT: ret i8 [[LOAD]] +; + %gep1 = getelementptr inbounds i8, ptr @constarrayi8, i64 %idx1 + %gep = getelementptr inbounds i8, ptr %gep1, i64 %idx2 + %load = load i8, ptr %gep + ret i8 %load +}