[X86] ABI change for x86-32: pass 3 vector arguments in-register instead of 4, except on Darwin.

This changes the ABI used on 32-bit x86 for passing vector arguments. 
Historically, clang passes the first 4 vector arguments in-register, and additional vector arguments on the stack, regardless of platform. That is different from the behavior of gcc, icc, and msvc, all of which pass only the first 3 arguments in-register.
The 3-register convention is documented, unofficially, in Agner's calling convention guide, and, officially, in the recently released version 1.0 of the i386 psABI.

Darwin is kept as is because the OS X ABI Function Call Guide explicitly documents the current (4-register) behavior.

This fixes PR21510

Differential revision: http://reviews.llvm.org/D9644

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237682 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Kuperstein 2015-05-19 11:06:56 +00:00
parent ef3ec7c783
commit 5440f2198d
4 changed files with 114 additions and 29 deletions

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@ -445,9 +445,61 @@ def CC_X86_64_AnyReg : CallingConv<[
// X86 C Calling Convention
//===----------------------------------------------------------------------===//
/// CC_X86_32_Vector_Common - In all X86-32 calling conventions, extra vector
/// values are spilled on the stack.
def CC_X86_32_Vector_Common : CallingConv<[
// Other SSE vectors get 16-byte stack slots that are 16-byte aligned.
CCIfType<[v16i8, v8i16, v4i32, v2i64, v4f32, v2f64], CCAssignToStack<16, 16>>,
// 256-bit AVX vectors get 32-byte stack slots that are 32-byte aligned.
CCIfType<[v32i8, v16i16, v8i32, v4i64, v8f32, v4f64],
CCAssignToStack<32, 32>>,
// 512-bit AVX 512-bit vectors get 64-byte stack slots that are 64-byte aligned.
CCIfType<[v64i8, v32i16, v16i32, v8i64, v16f32, v8f64],
CCAssignToStack<64, 64>>
]>;
// CC_X86_32_Vector_Standard - The first 3 vector arguments are passed in
// vector registers
def CC_X86_32_Vector_Standard : CallingConv<[
// SSE vector arguments are passed in XMM registers.
CCIfNotVarArg<CCIfType<[v16i8, v8i16, v4i32, v2i64, v4f32, v2f64],
CCAssignToReg<[XMM0, XMM1, XMM2]>>>,
// AVX 256-bit vector arguments are passed in YMM registers.
CCIfNotVarArg<CCIfType<[v32i8, v16i16, v8i32, v4i64, v8f32, v4f64],
CCIfSubtarget<"hasFp256()",
CCAssignToReg<[YMM0, YMM1, YMM2]>>>>,
// AVX 512-bit vector arguments are passed in ZMM registers.
CCIfNotVarArg<CCIfType<[v64i8, v32i16, v16i32, v8i64, v16f32, v8f64],
CCAssignToReg<[ZMM0, ZMM1, ZMM2]>>>,
CCDelegateTo<CC_X86_32_Vector_Common>
]>;
// CC_X86_32_Vector_Darwin - The first 4 vector arguments are passed in
// vector registers.
def CC_X86_32_Vector_Darwin : CallingConv<[
// SSE vector arguments are passed in XMM registers.
CCIfNotVarArg<CCIfType<[v16i8, v8i16, v4i32, v2i64, v4f32, v2f64],
CCAssignToReg<[XMM0, XMM1, XMM2, XMM3]>>>,
// AVX 256-bit vector arguments are passed in YMM registers.
CCIfNotVarArg<CCIfType<[v32i8, v16i16, v8i32, v4i64, v8f32, v4f64],
CCIfSubtarget<"hasFp256()",
CCAssignToReg<[YMM0, YMM1, YMM2, YMM3]>>>>,
// AVX 512-bit vector arguments are passed in ZMM registers.
CCIfNotVarArg<CCIfType<[v64i8, v32i16, v16i32, v8i64, v16f32, v8f64],
CCAssignToReg<[ZMM0, ZMM1, ZMM2, ZMM3]>>>,
CCDelegateTo<CC_X86_32_Vector_Common>
]>;
/// CC_X86_32_Common - In all X86-32 calling conventions, extra integers and FP
/// values are spilled on the stack, and the first 4 vector values go in XMM
/// regs.
/// values are spilled on the stack.
def CC_X86_32_Common : CallingConv<[
// Handles byval parameters.
CCIfByVal<CCPassByVal<4, 4>>,
@ -483,33 +535,16 @@ def CC_X86_32_Common : CallingConv<[
CCIfType<[v32i1], CCPromoteToType<v32i8>>,
CCIfType<[v64i1], CCPromoteToType<v64i8>>,
// The first 4 SSE vector arguments are passed in XMM registers.
CCIfNotVarArg<CCIfType<[v16i8, v8i16, v4i32, v2i64, v4f32, v2f64],
CCAssignToReg<[XMM0, XMM1, XMM2, XMM3]>>>,
// The first 4 AVX 256-bit vector arguments are passed in YMM registers.
CCIfNotVarArg<CCIfType<[v32i8, v16i16, v8i32, v4i64, v8f32, v4f64],
CCIfSubtarget<"hasFp256()",
CCAssignToReg<[YMM0, YMM1, YMM2, YMM3]>>>>,
// The first 4 AVX 512-bit vector arguments are passed in ZMM registers.
CCIfNotVarArg<CCIfType<[v64i8, v32i16, v16i32, v8i64, v16f32, v8f64],
CCAssignToReg<[ZMM0, ZMM1, ZMM2, ZMM3]>>>,
// Other SSE vectors get 16-byte stack slots that are 16-byte aligned.
CCIfType<[v16i8, v8i16, v4i32, v2i64, v4f32, v2f64], CCAssignToStack<16, 16>>,
// 256-bit AVX vectors get 32-byte stack slots that are 32-byte aligned.
CCIfType<[v32i8, v16i16, v8i32, v4i64, v8f32, v4f64],
CCAssignToStack<32, 32>>,
// 512-bit AVX 512-bit vectors get 64-byte stack slots that are 64-byte aligned.
CCIfType<[v64i8, v32i16, v16i32, v8i64, v16f32, v8f64],
CCAssignToStack<64, 64>>,
// __m64 vectors get 8-byte stack slots that are 4-byte aligned. They are
// passed in the parameter area.
CCIfType<[x86mmx], CCAssignToStack<8, 4>>]>;
CCIfType<[x86mmx], CCAssignToStack<8, 4>>,
// Darwin passes vectors in a form that differs from the i386 psABI
CCIfSubtarget<"isTargetDarwin()", CCDelegateTo<CC_X86_32_Vector_Darwin>>,
// Otherwise, drop to 'normal' X86-32 CC
CCDelegateTo<CC_X86_32_Vector_Standard>
]>;
def CC_X86_32_C : CallingConv<[
// Promote i1/i8/i16 arguments to i32.

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@ -1,6 +1,8 @@
; RUN: llc < %s -march=x86 -mcpu=corei7 | FileCheck %s
; RUN: llc < %s -march=x86 -mcpu=core-avx-i | FileCheck %s --check-prefix=AVX
target triple = "i686-pc-linux-gnu"
define <1 x float> @test1(<1 x double> %x) nounwind {
; CHECK-LABEL: test1:
; CHECK: # BB#0:
@ -59,12 +61,14 @@ define <4 x float> @test3(<4 x double> %x) nounwind {
define <8 x float> @test4(<8 x double> %x) nounwind {
; CHECK-LABEL: test4:
; CHECK: # BB#0:
; CHECK-NEXT: subl $12, %esp
; CHECK-NEXT: cvtpd2ps %xmm1, %xmm1
; CHECK-NEXT: cvtpd2ps %xmm0, %xmm0
; CHECK-NEXT: unpcklpd {{.*#+}} xmm0 = xmm0[0],xmm1[0]
; CHECK-NEXT: cvtpd2ps %xmm3, %xmm3
; CHECK-NEXT: cvtpd2ps %xmm2, %xmm1
; CHECK-NEXT: unpcklpd {{.*#+}} xmm1 = xmm1[0],xmm3[0]
; CHECK-NEXT: cvtpd2ps 16(%esp), %xmm2
; CHECK-NEXT: unpcklpd {{.*#+}} xmm1 = xmm1[0],xmm2[0]
; CHECK-NEXT: addl $12, %esp
; CHECK-NEXT: retl
;
; AVX-LABEL: test4:

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@ -3,6 +3,8 @@
; RUN: llc < %s -march=x86 -mattr=+sse2 -mcpu=nehalem | grep "addps %xmm3, %xmm1"
; RUN: llc < %s -march=x86 -mattr=+sse2 -mcpu=nehalem | grep "addps %xmm2, %xmm0"
target triple = "i686-apple-darwin8"
define <4 x double> @foo(<4 x double> %x, <4 x double> %z) {
%y = fmul <4 x double> %x, %z
ret <4 x double> %y

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@ -0,0 +1,44 @@
; RUN: llc < %s -mtriple=i686-apple-darwin -mattr=+avx512f | FileCheck %s --check-prefix=DARWIN
; RUN: llc < %s -mtriple=i686-pc-linux -mattr=+avx512f | FileCheck %s --check-prefix=LINUX
; CHECK-LABEL: test_sse:
; DARWIN-DAG: vpaddd %xmm1, %xmm0, %xmm0
; DARWIN-DAG: vpaddd %xmm3, %xmm2, %xmm1
; DARWIN: vpaddd %xmm1, %xmm0, %xmm0
; LINUX-DAG: vpaddd %xmm1, %xmm0, %xmm0
; LINUX-DAG: vpaddd {{[0-9]+}}(%e{{s|b}}p), %xmm2, %xmm1
; LINUX: vpaddd %xmm1, %xmm0, %xmm0
define <4 x i32> @test_sse(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c, <4 x i32> %d) nounwind {
%r0 = add <4 x i32> %a, %b
%r1 = add <4 x i32> %c, %d
%ret = add <4 x i32> %r0, %r1
ret <4 x i32> %ret
}
; CHECK-LABEL: test_avx:
; DARWIN-DAG: vpaddd %ymm1, %ymm0, %ymm0
; DARWIN-DAG: vpaddd %ymm3, %ymm2, %ymm1
; DARWIN: vpaddd %ymm1, %ymm0, %ymm0
; LINUX-DAG: vpaddd %ymm1, %ymm0, %ymm0
; LINUX-DAG: vpaddd {{[0-9]+}}(%e{{s|b}}p), %ymm2, %ymm1
; LINUX: vpaddd %ymm1, %ymm0, %ymm0
define <8 x i32> @test_avx(<8 x i32> %a, <8 x i32> %b, <8 x i32> %c, <8 x i32> %d) nounwind {
%r0 = add <8 x i32> %a, %b
%r1 = add <8 x i32> %c, %d
%ret = add <8 x i32> %r0, %r1
ret <8 x i32> %ret
}
; CHECK-LABEL: test_avx512:
; DARWIN-DAG: vpaddd %zmm1, %zmm0, %zmm0
; DARWIN-DAG: vpaddd %zmm3, %zmm2, %zmm1
; DARWIN: vpaddd %zmm1, %zmm0, %zmm0
; LINUX-DAG: vpaddd %zmm1, %zmm0, %zmm0
; LINUX-DAG: vpaddd {{[0-9]+}}(%e{{s|b}}p), %zmm2, %zmm1
; LINUX: vpaddd %zmm1, %zmm0, %zmm0
define <16 x i32> @test_avx512(<16 x i32> %a, <16 x i32> %b, <16 x i32> %c, <16 x i32> %d) nounwind {
%r0 = add <16 x i32> %a, %b
%r1 = add <16 x i32> %c, %d
%ret = add <16 x i32> %r0, %r1
ret <16 x i32> %ret
}