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[Clang] Freeze padded vectors before storing. (llvm#164821)
Currently Clang usually leaves padding bits uninitialized, which means they are undef at the moment. When expanding stores of vector types to include padding, the padding lanes will be poison, hence the padding bits will be poison. This interacts badly with coercion of arguments and return values, where 3 x float vectors will be loaded as i128 integer; poisoning the padding bits will make the whole value poison. Not sure if there's a better way, but I think we have a number of places that currently rely on the padding being undef, not poison. PR: llvm#164821
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4 files changed

+63
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‎clang/lib/CodeGen/CGExpr.cpp‎

Lines changed: 6 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2297,9 +2297,13 @@ void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, Address Addr,
22972297
CGM.getABIInfo().getOptimalVectorMemoryType(VecTy, getLangOpts());
22982298
if (!ClangVecTy->isPackedVectorBoolType(getContext()) &&
22992299
VecTy != NewVecTy) {
2300-
SmallVector<int, 16> Mask(NewVecTy->getNumElements(), -1);
2300+
SmallVector<int, 16> Mask(NewVecTy->getNumElements(),
2301+
VecTy->getNumElements());
23012302
std::iota(Mask.begin(), Mask.begin() + VecTy->getNumElements(), 0);
2302-
Value = Builder.CreateShuffleVector(Value, Mask, "extractVec");
2303+
// Use undef instead of poison for the padding lanes, to make sure no
2304+
// padding bits are poisoned, which may break coercion.
2305+
Value = Builder.CreateShuffleVector(Value, llvm::UndefValue::get(VecTy),
2306+
Mask, "extractVec");
23032307
SrcTy = NewVecTy;
23042308
}
23052309
if (Addr.getElementType() != SrcTy)

‎clang/test/CodeGen/AArch64/ext-vector-coercion.c‎

Lines changed: 42 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,42 @@
1+
// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 6
2+
// RUN: %clang_cc1 -fenable-matrix -triple arm64-apple-macosx %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s
3+
4+
typedef float float3 __attribute__((ext_vector_type(3)));
5+
struct Vec3 {
6+
union {
7+
struct {
8+
float x;
9+
float y;
10+
float z;
11+
};
12+
float vec __attribute__((ext_vector_type(3)));
13+
};
14+
};
15+
16+
// CHECK-LABEL: define i128 @add(
17+
// CHECK-SAME: i128 [[A_COERCE:%.*]]) #[[ATTR0:[0-9]+]] {
18+
// CHECK-NEXT: [[ENTRY:.*:]]
19+
// CHECK-NEXT: [[RETVAL:%.*]] = alloca [[STRUCT_VEC3:%.*]], align 16
20+
// CHECK-NEXT: [[A:%.*]] = alloca [[STRUCT_VEC3]], align 16
21+
// CHECK-NEXT: [[COERCE_DIVE:%.*]] = getelementptr inbounds nuw [[STRUCT_VEC3]], ptr [[A]], i32 0, i32 0
22+
// CHECK-NEXT: store i128 [[A_COERCE]], ptr [[COERCE_DIVE]], align 16
23+
// CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds nuw [[STRUCT_VEC3]], ptr [[A]], i32 0, i32 0
24+
// CHECK-NEXT: [[LOADVECN:%.*]] = load <4 x float>, ptr [[TMP0]], align 16
25+
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <4 x float> [[LOADVECN]], <4 x float> poison, <3 x i32> <i32 0, i32 1, i32 2>
26+
// CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds nuw [[STRUCT_VEC3]], ptr [[A]], i32 0, i32 0
27+
// CHECK-NEXT: [[LOADVECN1:%.*]] = load <4 x float>, ptr [[TMP1]], align 16
28+
// CHECK-NEXT: [[EXTRACTVEC2:%.*]] = shufflevector <4 x float> [[LOADVECN1]], <4 x float> poison, <3 x i32> <i32 0, i32 1, i32 2>
29+
// CHECK-NEXT: [[ADD:%.*]] = fadd <3 x float> [[EXTRACTVEC]], [[EXTRACTVEC2]]
30+
// CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds nuw [[STRUCT_VEC3]], ptr [[RETVAL]], i32 0, i32 0
31+
// CHECK-NEXT: [[EXTRACTVEC3:%.*]] = shufflevector <3 x float> [[ADD]], <3 x float> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
32+
// CHECK-NEXT: store <4 x float> [[EXTRACTVEC3]], ptr [[TMP2]], align 16
33+
// CHECK-NEXT: [[COERCE_DIVE4:%.*]] = getelementptr inbounds nuw [[STRUCT_VEC3]], ptr [[RETVAL]], i32 0, i32 0
34+
// CHECK-NEXT: [[TMP3:%.*]] = load i128, ptr [[COERCE_DIVE4]], align 16
35+
// CHECK-NEXT: ret i128 [[TMP3]]
36+
//
37+
struct Vec3 add(struct Vec3 a) {
38+
struct Vec3 res;
39+
res.vec = a.vec + a.vec;
40+
return res;
41+
}
42+

‎clang/test/CodeGenCXX/matrix-vector-bit-int.cpp‎

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -19,7 +19,7 @@ using i4x3x3 = _BitInt(4) __attribute__((matrix_type(3, 3)));
1919
// CHECK-NEXT: store i32 [[A_COERCE]], ptr [[A]], align 4
2020
// CHECK-NEXT: [[LOADVECN:%.*]] = load <4 x i8>, ptr [[A]], align 4
2121
// CHECK-NEXT: [[A1:%.*]] = shufflevector <4 x i8> [[LOADVECN]], <4 x i8> poison, <3 x i32> <i32 0, i32 1, i32 2>
22-
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i8> [[A1]], <3 x i8> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
22+
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i8> [[A1]], <3 x i8> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
2323
// CHECK-NEXT: store <4 x i8> [[EXTRACTVEC]], ptr [[A_ADDR]], align 4
2424
// CHECK-NEXT: [[LOADVECN2:%.*]] = load <4 x i8>, ptr [[A_ADDR]], align 4
2525
// CHECK-NEXT: [[EXTRACTVEC3:%.*]] = shufflevector <4 x i8> [[LOADVECN2]], <4 x i8> poison, <3 x i32> <i32 0, i32 1, i32 2>
@@ -38,7 +38,7 @@ i8x3 v1(i8x3 a) {
3838
// CHECK-SAME: <3 x i32> noundef [[A:%.*]]) #[[ATTR1:[0-9]+]] {
3939
// CHECK-NEXT: [[ENTRY:.*:]]
4040
// CHECK-NEXT: [[A_ADDR:%.*]] = alloca <3 x i32>, align 16
41-
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i32> [[A]], <3 x i32> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
41+
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i32> [[A]], <3 x i32> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
4242
// CHECK-NEXT: store <4 x i32> [[EXTRACTVEC]], ptr [[A_ADDR]], align 16
4343
// CHECK-NEXT: [[LOADVECN:%.*]] = load <4 x i32>, ptr [[A_ADDR]], align 16
4444
// CHECK-NEXT: [[EXTRACTVEC1:%.*]] = shufflevector <4 x i32> [[LOADVECN]], <4 x i32> poison, <3 x i32> <i32 0, i32 1, i32 2>
@@ -57,7 +57,7 @@ i32x3 v2(i32x3 a) {
5757
// CHECK-NEXT: [[A_ADDR:%.*]] = alloca <3 x i512>, align 256
5858
// CHECK-NEXT: [[LOADVECN:%.*]] = load <4 x i512>, ptr [[TMP0]], align 256
5959
// CHECK-NEXT: [[A:%.*]] = shufflevector <4 x i512> [[LOADVECN]], <4 x i512> poison, <3 x i32> <i32 0, i32 1, i32 2>
60-
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i512> [[A]], <3 x i512> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
60+
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i512> [[A]], <3 x i512> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
6161
// CHECK-NEXT: store <4 x i512> [[EXTRACTVEC]], ptr [[A_ADDR]], align 256
6262
// CHECK-NEXT: [[LOADVECN1:%.*]] = load <4 x i512>, ptr [[A_ADDR]], align 256
6363
// CHECK-NEXT: [[EXTRACTVEC2:%.*]] = shufflevector <4 x i512> [[LOADVECN1]], <4 x i512> poison, <3 x i32> <i32 0, i32 1, i32 2>
@@ -80,7 +80,7 @@ i512x3 v3(i512x3 a) {
8080
// CHECK-NEXT: store i32 [[A_COERCE]], ptr [[A]], align 4
8181
// CHECK-NEXT: [[LOADVECN:%.*]] = load <4 x i4>, ptr [[A]], align 4
8282
// CHECK-NEXT: [[A1:%.*]] = shufflevector <4 x i4> [[LOADVECN]], <4 x i4> poison, <3 x i32> <i32 0, i32 1, i32 2>
83-
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i4> [[A1]], <3 x i4> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
83+
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i4> [[A1]], <3 x i4> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
8484
// CHECK-NEXT: store <4 x i4> [[EXTRACTVEC]], ptr [[A_ADDR]], align 4
8585
// CHECK-NEXT: [[LOADVECN2:%.*]] = load <4 x i4>, ptr [[A_ADDR]], align 4
8686
// CHECK-NEXT: [[EXTRACTVEC3:%.*]] = shufflevector <4 x i4> [[LOADVECN2]], <4 x i4> poison, <3 x i32> <i32 0, i32 1, i32 2>

‎clang/test/CodeGenOpenCL/preserve_vec3.cl‎

Lines changed: 11 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,7 @@ typedef float float4 __attribute__((ext_vector_type(4)));
1212
// CHECK-SAME: ptr addrspace(1) noundef readonly align 16 captures(none) [[A:%.*]], ptr addrspace(1) noundef writeonly align 16 captures(none) initializes((0, 16)) [[B:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] !kernel_arg_addr_space [[META7:![0-9]+]] !kernel_arg_access_qual [[META8:![0-9]+]] !kernel_arg_type [[META9:![0-9]+]] !kernel_arg_base_type [[META10:![0-9]+]] !kernel_arg_type_qual [[META11:![0-9]+]] {
1313
// CHECK-NEXT: [[ENTRY:.*:]]
1414
// CHECK-NEXT: [[TMP0:%.*]] = load <3 x float>, ptr addrspace(1) [[A]], align 16
15-
// CHECK-NEXT: [[EXTRACTVEC1_I:%.*]] = shufflevector <3 x float> [[TMP0]], <3 x float> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
15+
// CHECK-NEXT: [[EXTRACTVEC1_I:%.*]] = shufflevector <3 x float> [[TMP0]], <3 x float> <float undef, float poison, float poison>, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
1616
// CHECK-NEXT: store <4 x float> [[EXTRACTVEC1_I]], ptr addrspace(1) [[B]], align 16, !tbaa [[CHAR_TBAA12:![0-9]+]]
1717
// CHECK-NEXT: ret void
1818
//
@@ -24,7 +24,7 @@ void kernel foo(global float3 *a, global float3 *b) {
2424
// CHECK-SAME: ptr addrspace(1) noundef writeonly align 16 captures(none) initializes((0, 16)) [[A:%.*]], ptr addrspace(1) noundef readonly align 16 captures(none) [[B:%.*]]) local_unnamed_addr #[[ATTR0]] !kernel_arg_addr_space [[META7]] !kernel_arg_access_qual [[META8]] !kernel_arg_type [[META13:![0-9]+]] !kernel_arg_base_type [[META14:![0-9]+]] !kernel_arg_type_qual [[META11]] {
2525
// CHECK-NEXT: [[ENTRY:.*:]]
2626
// CHECK-NEXT: [[TMP0:%.*]] = load <3 x float>, ptr addrspace(1) [[B]], align 16, !tbaa [[CHAR_TBAA12]]
27-
// CHECK-NEXT: [[EXTRACTVEC_I:%.*]] = shufflevector <3 x float> [[TMP0]], <3 x float> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
27+
// CHECK-NEXT: [[EXTRACTVEC_I:%.*]] = shufflevector <3 x float> [[TMP0]], <3 x float> <float undef, float poison, float poison>, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
2828
// CHECK-NEXT: store <4 x float> [[EXTRACTVEC_I]], ptr addrspace(1) [[A]], align 16, !tbaa [[CHAR_TBAA12]]
2929
// CHECK-NEXT: ret void
3030
//
@@ -60,7 +60,7 @@ void kernel float3_to_double2(global float3 *a, global double2 *b) {
6060
// CHECK-SAME: ptr addrspace(1) noundef writeonly align 8 captures(none) initializes((0, 8)) [[A:%.*]], ptr addrspace(1) noundef readonly align 8 captures(none) [[B:%.*]]) local_unnamed_addr #[[ATTR0]] !kernel_arg_addr_space [[META7]] !kernel_arg_access_qual [[META8]] !kernel_arg_type [[META17:![0-9]+]] !kernel_arg_base_type [[META18:![0-9]+]] !kernel_arg_type_qual [[META11]] {
6161
// CHECK-NEXT: [[ENTRY:.*:]]
6262
// CHECK-NEXT: [[TMP0:%.*]] = load <3 x i16>, ptr addrspace(1) [[B]], align 8, !tbaa [[CHAR_TBAA12]]
63-
// CHECK-NEXT: [[EXTRACTVEC_I:%.*]] = shufflevector <3 x i16> [[TMP0]], <3 x i16> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
63+
// CHECK-NEXT: [[EXTRACTVEC_I:%.*]] = shufflevector <3 x i16> [[TMP0]], <3 x i16> <i16 undef, i16 poison, i16 poison>, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
6464
// CHECK-NEXT: store <4 x i16> [[EXTRACTVEC_I]], ptr addrspace(1) [[A]], align 8, !tbaa [[CHAR_TBAA12]]
6565
// CHECK-NEXT: ret void
6666
//
@@ -71,8 +71,8 @@ void kernel char8_to_short3(global short3 *a, global char8 *b) {
7171
// CHECK-LABEL: define dso_local spir_func void @from_char3(
7272
// CHECK-SAME: <3 x i8> noundef [[A:%.*]], ptr addrspace(1) noundef writeonly captures(none) initializes((0, 4)) [[OUT:%.*]]) local_unnamed_addr #[[ATTR2:[0-9]+]] {
7373
// CHECK-NEXT: [[ENTRY:.*:]]
74-
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i8> [[A]], <3 x i8> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
75-
// CHECK-NEXT: store <4 x i8> [[EXTRACTVEC]], ptr addrspace(1) [[OUT]], align 4, !tbaa [[INT_TBAA3:![0-9]+]]
74+
// CHECK-NEXT: [[TMP0:%.*]] = shufflevector <3 x i8> [[A]], <3 x i8> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
75+
// CHECK-NEXT: store <4 x i8> [[TMP0]], ptr addrspace(1) [[OUT]], align 4, !tbaa [[INT_TBAA3:![0-9]+]]
7676
// CHECK-NEXT: ret void
7777
//
7878
void from_char3(char3 a, global int *out) {
@@ -82,8 +82,8 @@ void from_char3(char3 a, global int *out) {
8282
// CHECK-LABEL: define dso_local spir_func void @from_short3(
8383
// CHECK-SAME: <3 x i16> noundef [[A:%.*]], ptr addrspace(1) noundef writeonly captures(none) initializes((0, 8)) [[OUT:%.*]]) local_unnamed_addr #[[ATTR2]] {
8484
// CHECK-NEXT: [[ENTRY:.*:]]
85-
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i16> [[A]], <3 x i16> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
86-
// CHECK-NEXT: store <4 x i16> [[EXTRACTVEC]], ptr addrspace(1) [[OUT]], align 8, !tbaa [[LONG_TBAA19:![0-9]+]]
85+
// CHECK-NEXT: [[TMP0:%.*]] = shufflevector <3 x i16> [[A]], <3 x i16> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
86+
// CHECK-NEXT: store <4 x i16> [[TMP0]], ptr addrspace(1) [[OUT]], align 8, !tbaa [[LONG_TBAA19:![0-9]+]]
8787
// CHECK-NEXT: ret void
8888
//
8989
void from_short3(short3 a, global long *out) {
@@ -94,7 +94,8 @@ void from_short3(short3 a, global long *out) {
9494
// CHECK-SAME: i32 noundef [[A:%.*]], ptr addrspace(1) noundef writeonly captures(none) initializes((0, 4)) [[OUT:%.*]]) local_unnamed_addr #[[ATTR2]] {
9595
// CHECK-NEXT: [[ENTRY:.*:]]
9696
// CHECK-NEXT: [[TMP0:%.*]] = bitcast i32 [[A]] to <4 x i8>
97-
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <4 x i8> [[TMP0]], <4 x i8> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
97+
// CHECK-NEXT: [[ASTYPE:%.*]] = shufflevector <4 x i8> [[TMP0]], <4 x i8> poison, <3 x i32> <i32 0, i32 1, i32 2>
98+
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i8> [[ASTYPE]], <3 x i8> <i8 undef, i8 poison, i8 poison>, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
9899
// CHECK-NEXT: store <4 x i8> [[EXTRACTVEC]], ptr addrspace(1) [[OUT]], align 4, !tbaa [[CHAR_TBAA12]]
99100
// CHECK-NEXT: ret void
100101
//
@@ -106,7 +107,8 @@ void scalar_to_char3(int a, global char3 *out) {
106107
// CHECK-SAME: i64 noundef [[A:%.*]], ptr addrspace(1) noundef writeonly captures(none) initializes((0, 8)) [[OUT:%.*]]) local_unnamed_addr #[[ATTR2]] {
107108
// CHECK-NEXT: [[ENTRY:.*:]]
108109
// CHECK-NEXT: [[TMP0:%.*]] = bitcast i64 [[A]] to <4 x i16>
109-
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <4 x i16> [[TMP0]], <4 x i16> poison, <4 x i32> <i32 0, i32 1, i32 2, i32 poison>
110+
// CHECK-NEXT: [[ASTYPE:%.*]] = shufflevector <4 x i16> [[TMP0]], <4 x i16> poison, <3 x i32> <i32 0, i32 1, i32 2>
111+
// CHECK-NEXT: [[EXTRACTVEC:%.*]] = shufflevector <3 x i16> [[ASTYPE]], <3 x i16> <i16 undef, i16 poison, i16 poison>, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
110112
// CHECK-NEXT: store <4 x i16> [[EXTRACTVEC]], ptr addrspace(1) [[OUT]], align 8, !tbaa [[CHAR_TBAA12]]
111113
// CHECK-NEXT: ret void
112114
//

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