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[InstCombine] Bail out of load-store forwarding for scalable vector t…
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…ypes

This patch fixes an invalid TypeSize->uint64_t implicit conversion in
FoldReinterpretLoadFromConst. If the size of the constant is scalable
we bail out of the optimisation for now.

Tests added here:

  Transforms/InstCombine/load-store-forward.ll

Differential Revision: https://reviews.llvm.org/D120240

(cherry picked from commit 47eff64)
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@david-arm @tstellar
david-arm authored and tstellar committed Feb 28, 2022
1 parent 4fe93c0 commit 64534d2
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Showing 2 changed files with 175 additions and 3 deletions.
9 changes: 6 additions & 3 deletions llvm/lib/Analysis/ConstantFolding.cpp
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Expand Up @@ -589,14 +589,17 @@ Constant *FoldReinterpretLoadFromConst(Constant *C, Type *LoadTy,
if (BytesLoaded > 32 || BytesLoaded == 0)
return nullptr;

int64_t InitializerSize = DL.getTypeAllocSize(C->getType()).getFixedSize();

// If we're not accessing anything in this constant, the result is undefined.
if (Offset <= -1 * static_cast<int64_t>(BytesLoaded))
return UndefValue::get(IntType);

// TODO: We should be able to support scalable types.
TypeSize InitializerSize = DL.getTypeAllocSize(C->getType());
if (InitializerSize.isScalable())
return nullptr;

// If we're not accessing anything in this constant, the result is undefined.
if (Offset >= InitializerSize)
if (Offset >= InitializerSize.getFixedValue())
return UndefValue::get(IntType);

unsigned char RawBytes[32] = {0};
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169 changes: 169 additions & 0 deletions llvm/test/Transforms/InstCombine/load-store-forward.ll
View file
Expand Up @@ -120,3 +120,172 @@ define i32 @vec_store_load_overlap(i32* %p) {
%load = load i32, i32* %p5, align 2
ret i32 %load
}

define i32 @load_i32_store_nxv4i32(i32* %a) {
; CHECK-LABEL: @load_i32_store_nxv4i32(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i32* [[A:%.*]] to <vscale x 4 x i32>*
; CHECK-NEXT: store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* [[TMP0]], align 16
; CHECK-NEXT: [[TMP1:%.*]] = load i32, i32* [[A]], align 4
; CHECK-NEXT: ret i32 [[TMP1]]
;
entry:
%0 = bitcast i32* %a to <vscale x 4 x i32>*
store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* %0, align 16
%1 = load i32, i32* %a, align 4
ret i32 %1
}

define i64 @load_i64_store_nxv8i8(i8* %a) {
; CHECK-LABEL: @load_i64_store_nxv8i8(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i8* [[A:%.*]] to <vscale x 8 x i8>*
; CHECK-NEXT: store <vscale x 8 x i8> shufflevector (<vscale x 8 x i8> insertelement (<vscale x 8 x i8> poison, i8 1, i32 0), <vscale x 8 x i8> poison, <vscale x 8 x i32> zeroinitializer), <vscale x 8 x i8>* [[TMP0]], align 16
; CHECK-NEXT: [[A2:%.*]] = bitcast i8* [[A]] to i64*
; CHECK-NEXT: [[LOAD:%.*]] = load i64, i64* [[A2]], align 8
; CHECK-NEXT: ret i64 [[LOAD]]
;
entry:
%0 = bitcast i8* %a to <vscale x 8 x i8>*
store <vscale x 8 x i8> shufflevector (<vscale x 8 x i8> insertelement (<vscale x 8 x i8> poison, i8 1, i32 0), <vscale x 8 x i8> poison, <vscale x 8 x i32> zeroinitializer), <vscale x 8 x i8>* %0, align 16
%a2 = bitcast i8* %a to i64*
%load = load i64, i64* %a2, align 8
ret i64 %load
}

define i64 @load_i64_store_nxv4i32(i32* %a) {
; CHECK-LABEL: @load_i64_store_nxv4i32(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i32* [[A:%.*]] to <vscale x 4 x i32>*
; CHECK-NEXT: store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* [[TMP0]], align 16
; CHECK-NEXT: [[A2:%.*]] = bitcast i32* [[A]] to i64*
; CHECK-NEXT: [[LOAD:%.*]] = load i64, i64* [[A2]], align 8
; CHECK-NEXT: ret i64 [[LOAD]]
;
entry:
%0 = bitcast i32* %a to <vscale x 4 x i32>*
store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* %0, align 16
%a2 = bitcast i32* %a to i64*
%load = load i64, i64* %a2, align 8
ret i64 %load
}

define i8 @load_i8_store_nxv4i32(i32* %a) {
; CHECK-LABEL: @load_i8_store_nxv4i32(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i32* [[A:%.*]] to <vscale x 4 x i32>*
; CHECK-NEXT: store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* [[TMP0]], align 16
; CHECK-NEXT: [[A2:%.*]] = bitcast i32* [[A]] to i8*
; CHECK-NEXT: [[LOAD:%.*]] = load i8, i8* [[A2]], align 1
; CHECK-NEXT: ret i8 [[LOAD]]
;
entry:
%0 = bitcast i32* %a to <vscale x 4 x i32>*
store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* %0, align 16
%a2 = bitcast i32* %a to i8*
%load = load i8, i8* %a2, align 1
ret i8 %load
}

define float @load_f32_store_nxv4f32(float* %a) {
; CHECK-LABEL: @load_f32_store_nxv4f32(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast float* [[A:%.*]] to <vscale x 4 x float>*
; CHECK-NEXT: store <vscale x 4 x float> shufflevector (<vscale x 4 x float> insertelement (<vscale x 4 x float> poison, float 1.000000e+00, i64 0), <vscale x 4 x float> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x float>* [[TMP0]], align 16
; CHECK-NEXT: [[TMP1:%.*]] = load float, float* [[A]], align 4
; CHECK-NEXT: ret float [[TMP1]]
;
entry:
%0 = bitcast float* %a to <vscale x 4 x float>*
store <vscale x 4 x float> shufflevector (<vscale x 4 x float> insertelement (<vscale x 4 x float> poison, float 1.0, i64 0), <vscale x 4 x float> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x float>* %0, align 16
%1 = load float, float* %a, align 4
ret float %1
}

define i32 @load_i32_store_nxv4f32(float* %a) {
; CHECK-LABEL: @load_i32_store_nxv4f32(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast float* [[A:%.*]] to <vscale x 4 x float>*
; CHECK-NEXT: store <vscale x 4 x float> shufflevector (<vscale x 4 x float> insertelement (<vscale x 4 x float> poison, float 1.000000e+00, i64 0), <vscale x 4 x float> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x float>* [[TMP0]], align 16
; CHECK-NEXT: [[A2:%.*]] = bitcast float* [[A]] to i32*
; CHECK-NEXT: [[LOAD:%.*]] = load i32, i32* [[A2]], align 4
; CHECK-NEXT: ret i32 [[LOAD]]
;
entry:
%0 = bitcast float* %a to <vscale x 4 x float>*
store <vscale x 4 x float> shufflevector (<vscale x 4 x float> insertelement (<vscale x 4 x float> poison, float 1.0, i64 0), <vscale x 4 x float> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x float>* %0, align 16
%a2 = bitcast float* %a to i32*
%load = load i32, i32* %a2, align 4
ret i32 %load
}

define <4 x i32> @load_v4i32_store_nxv4i32(i32* %a) {
; CHECK-LABEL: @load_v4i32_store_nxv4i32(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i32* [[A:%.*]] to <vscale x 4 x i32>*
; CHECK-NEXT: store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* [[TMP0]], align 16
; CHECK-NEXT: [[TMP1:%.*]] = bitcast i32* [[A]] to <4 x i32>*
; CHECK-NEXT: [[TMP2:%.*]] = load <4 x i32>, <4 x i32>* [[TMP1]], align 16
; CHECK-NEXT: ret <4 x i32> [[TMP2]]
;
entry:
%0 = bitcast i32* %a to <vscale x 4 x i32>*
store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* %0, align 16
%1 = bitcast i32* %a to <4 x i32>*
%2 = load <4 x i32>, <4 x i32>* %1, align 16
ret <4 x i32> %2
}

define <4 x i16> @load_v4i16_store_nxv4i32(i32* %a) {
; CHECK-LABEL: @load_v4i16_store_nxv4i32(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i32* [[A:%.*]] to <vscale x 4 x i32>*
; CHECK-NEXT: store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* [[TMP0]], align 16
; CHECK-NEXT: [[TMP1:%.*]] = bitcast i32* [[A]] to <4 x i16>*
; CHECK-NEXT: [[TMP2:%.*]] = load <4 x i16>, <4 x i16>* [[TMP1]], align 16
; CHECK-NEXT: ret <4 x i16> [[TMP2]]
;
entry:
%0 = bitcast i32* %a to <vscale x 4 x i32>*
store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* %0, align 16
%1 = bitcast i32* %a to <4 x i16>*
%2 = load <4 x i16>, <4 x i16>* %1, align 16
ret <4 x i16> %2
}

; Loaded data type exceeds the known minimum size of the store.
define i64 @load_i64_store_nxv4i8(i8* %a) {
; CHECK-LABEL: @load_i64_store_nxv4i8(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i8* [[A:%.*]] to <vscale x 4 x i8>*
; CHECK-NEXT: store <vscale x 4 x i8> shufflevector (<vscale x 4 x i8> insertelement (<vscale x 4 x i8> poison, i8 1, i32 0), <vscale x 4 x i8> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i8>* [[TMP0]], align 16
; CHECK-NEXT: [[A2:%.*]] = bitcast i8* [[A]] to i64*
; CHECK-NEXT: [[LOAD:%.*]] = load i64, i64* [[A2]], align 8
; CHECK-NEXT: ret i64 [[LOAD]]
;
entry:
%0 = bitcast i8* %a to <vscale x 4 x i8>*
store <vscale x 4 x i8> shufflevector (<vscale x 4 x i8> insertelement (<vscale x 4 x i8> poison, i8 1, i32 0), <vscale x 4 x i8> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i8>* %0, align 16
%a2 = bitcast i8* %a to i64*
%load = load i64, i64* %a2, align 8
ret i64 %load
}

; Loaded data size is unknown - we cannot guarantee it won't
; exceed the store size.
define <vscale x 4 x i8> @load_nxv4i8_store_nxv4i32(i32* %a) {
; CHECK-LABEL: @load_nxv4i8_store_nxv4i32(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast i32* [[A:%.*]] to <vscale x 4 x i32>*
; CHECK-NEXT: store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* [[TMP0]], align 16
; CHECK-NEXT: [[TMP1:%.*]] = bitcast i32* [[A]] to <vscale x 4 x i8>*
; CHECK-NEXT: [[TMP2:%.*]] = load <vscale x 4 x i8>, <vscale x 4 x i8>* [[TMP1]], align 16
; CHECK-NEXT: ret <vscale x 4 x i8> [[TMP2]]
;
entry:
%0 = bitcast i32* %a to <vscale x 4 x i32>*
store <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 1, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer), <vscale x 4 x i32>* %0, align 16
%1 = bitcast i32* %a to <vscale x 4 x i8>*
%2 = load <vscale x 4 x i8>, <vscale x 4 x i8>* %1, align 16
ret <vscale x 4 x i8> %2
}

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