[clang] 1c4108a - [i386] Modify the alignment of m128/m256/__m512 vector type according i386 abi.

Wed Apr 14 01:57:32 PDT 2021

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On Wed, Apr 14, 2021 at 11:47 AM via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
>
>
> Author: Liu, Chen3
> Date: 2021-04-14T16:44:54+08:00
> New Revision: 1c4108ab661d43e21b1d1c804d8a403e5b0cf7d6
>
> URL: https://github.com/llvm/llvm-project/commit/1c4108ab661d43e21b1d1c804d8a403e5b0cf7d6
> DIFF: https://github.com/llvm/llvm-project/commit/1c4108ab661d43e21b1d1c804d8a403e5b0cf7d6.diff
>
> LOG: [i386] Modify the alignment of __m128/__m256/__m512 vector type according i386 abi.
>
> According to i386 System V ABI:
>
> 1. when __m256 are required to be passed on the stack, the stack pointer must be aligned on a 0 mod 32 byte boundary at the time of the call.
> 2. when __m512 are required to be passed on the stack, the stack pointer must be aligned on a 0 mod 64 byte boundary at the time of the call.
>
> The current method of clang passing __m512 parameter are as follow:
>
> 1. when target supports avx512, passing it with 64 byte alignment;
> 2. when target supports avx, passing it with 32 byte alignment;
> 3. Otherwise, passing it with 16 byte alignment.
>
> Passing __m256 parameter are as follow:
>
> 1. when target supports avx or avx512, passing it with 32 byte alignment;
> 2. Otherwise, passing it with 16 byte alignment.
>
> This pach will passing __m128/__m256/__m512 following i386 System V ABI and
> apply it to Linux only since other System V OS (e.g Darwin, PS4 and FreeBSD) don't
> want to spend any effort dealing with the ramifications of ABI breaks at present.
>
> Differential Revision: https://reviews.llvm.org/D78564
>
> Added:
>     clang/test/CodeGen/x86_32-align-linux.c
>
> Modified:
>     clang/lib/CodeGen/TargetInfo.cpp
>
> Removed:
>
>
>
> ################################################################################
> diff  --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
> index 7f4deb21d6ed..55e38741e287 100644
> --- a/clang/lib/CodeGen/TargetInfo.cpp
> +++ b/clang/lib/CodeGen/TargetInfo.cpp
> @@ -1105,6 +1105,7 @@ class X86_32ABIInfo : public SwiftABIInfo {
>    bool IsWin32StructABI;
>    bool IsSoftFloatABI;
>    bool IsMCUABI;
> +  bool IsLinuxABI;
>    unsigned DefaultNumRegisterParameters;
>
>    static bool isRegisterSize(unsigned Size) {
> @@ -1167,9 +1168,9 @@ class X86_32ABIInfo : public SwiftABIInfo {
>                  unsigned NumRegisterParameters, bool SoftFloatABI)
>      : SwiftABIInfo(CGT), IsDarwinVectorABI(DarwinVectorABI),
>        IsRetSmallStructInRegABI(RetSmallStructInRegABI),
> -      IsWin32StructABI(Win32StructABI),
> -      IsSoftFloatABI(SoftFloatABI),
> +      IsWin32StructABI(Win32StructABI), IsSoftFloatABI(SoftFloatABI),
>        IsMCUABI(CGT.getTarget().getTriple().isOSIAMCU()),
> +      IsLinuxABI(CGT.getTarget().getTriple().isOSLinux()),
>        DefaultNumRegisterParameters(NumRegisterParameters) {}
>
>    bool shouldPassIndirectlyForSwift(ArrayRef<llvm::Type*> scalars,
> @@ -1594,6 +1595,14 @@ unsigned X86_32ABIInfo::getTypeStackAlignInBytes(QualType Ty,
>    if (Align <= MinABIStackAlignInBytes)
>      return 0; // Use default alignment.
>
> +  if (IsLinuxABI) {
> +    // Exclude other System V OS (e.g Darwin, PS4 and FreeBSD) since we don't
> +    // want to spend any effort dealing with the ramifications of ABI breaks.
> +    //
> +    // If the vector type is __m128/__m256/__m512, return the default alignment.
> +    if (Ty->isVectorType() && (Align == 16 || Align == 32 || Align == 64))
> +      return Align;
> +  }
>    // On non-Darwin, the stack type alignment is always 4.
>    if (!IsDarwinVectorABI) {
>      // Set explicit alignment, since we may need to realign the top.
>
> diff  --git a/clang/test/CodeGen/x86_32-align-linux.c b/clang/test/CodeGen/x86_32-align-linux.c
> new file mode 100644
> index 000000000000..6e6ddd757b6f
> --- /dev/null
> +++ b/clang/test/CodeGen/x86_32-align-linux.c
> @@ -0,0 +1,60 @@
> +// RUN: %clang_cc1 -w -fblocks -ffreestanding -triple i386-pc-linux-gnu -emit-llvm -o - %s | FileCheck %s
> +// RUN: %clang_cc1 -w -fblocks -ffreestanding -triple i386-pc-linux-gnu -target-feature +avx -emit-llvm -o - %s | FileCheck %s
> +// RUN: %clang_cc1 -w -fblocks -ffreestanding -triple i386-pc-linux-gnu -target-feature +avx512f -emit-llvm -o - %s | FileCheck %s
> +
> +#include <immintrin.h>
> +
> +// CHECK-LABEL: define dso_local void @testm128
> +// CHECK-LABEL: %argp.cur = load i8*, i8** %args, align 4
> +// CHECK-NEXT:  %0 = ptrtoint i8* %argp.cur to i32
> +// CHECK-NEXT:  %1 = add i32 %0, 15
> +// CHECK-NEXT:  %2 = and i32 %1, -16
> +// CHECK-NEXT:  %argp.cur.aligned = inttoptr i32 %2 to i8*
> +void testm128(int argCount, ...) {
> +  __m128 res;
> +  __builtin_va_list args;
> +  __builtin_va_start(args, argCount);
> +  res = __builtin_va_arg(args, __m128);
> +  __builtin_va_end(args);
> +}
> +
> +// CHECK-LABEL: define dso_local void @testm256
> +// CHECK-LABEL: %argp.cur = load i8*, i8** %args, align 4
> +// CHECK-NEXT:  %0 = ptrtoint i8* %argp.cur to i32
> +// CHECK-NEXT:  %1 = add i32 %0, 31
> +// CHECK-NEXT:  %2 = and i32 %1, -32
> +// CHECK-NEXT:  %argp.cur.aligned = inttoptr i32 %2 to i8*
> +void testm256(int argCount, ...) {
> +  __m256 res;
> +  __builtin_va_list args;
> +  __builtin_va_start(args, argCount);
> +  res = __builtin_va_arg(args, __m256);
> +  __builtin_va_end(args);
> +}
> +
> +// CHECK-LABEL: define dso_local void @testm512
> +// CHECK-LABEL: %argp.cur = load i8*, i8** %args, align 4
> +// CHECK-NEXT:  %0 = ptrtoint i8* %argp.cur to i32
> +// CHECK-NEXT:  %1 = add i32 %0, 63
> +// CHECK-NEXT:  %2 = and i32 %1, -64
> +// CHECK-NEXT:  %argp.cur.aligned = inttoptr i32 %2 to i8*
> +void testm512(int argCount, ...) {
> +  __m512 res;
> +  __builtin_va_list args;
> +  __builtin_va_start(args, argCount);
> +  res = __builtin_va_arg(args, __m512);
> +  __builtin_va_end(args);
> +}
> +
> +// CHECK-LABEL: define dso_local void @testPastArguments
> +// CHECK: call void (i32, ...) @testm128(i32 1, <4 x float> %0)
> +// CHECK: call void (i32, ...) @testm256(i32 1, <8 x float> %1)
> +// CHECK: call void (i32, ...) @testm512(i32 1, <16 x float> %2)
> +void testPastArguments(void) {
> +  __m128 a;
> +  __m256 b;
> +  __m512 c;
> +  testm128(1, a);
> +  testm256(1, b);
> +  testm512(1, c);
> +}
>
>
>
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[clang] 1c4108a - [i386] Modify the alignment of __m128/__m256/__m512 vector type according i386 abi.

[clang] 1c4108a - [i386] Modify the alignment of m128/m256/__m512 vector type according i386 abi.