c166a43c6e
The new experimental calling convention preserve_none is the opposite side of existing preserve_all. It tries to preserve as few general registers as possible. So all general registers are caller saved registers. It can also uses more general registers to pass arguments. This attribute doesn't impact floating-point registers. Floating-point registers still follow the c calling convention. Currently preserve_none is supported on X86-64 only. It changes the c calling convention in following fields: * RSP and RBP are the only preserved general registers, all other general registers are caller saved registers. * We can use [RDI, RSI, RDX, RCX, R8, R9, R11, R12, R13, R14, R15, RAX] to pass arguments. It can improve the performance of hot tailcall chain, because many callee saved registers' save/restore instructions can be removed if the tail functions are using preserve_none. In my experiment in protocol buffer, the parsing functions are improved by 3% to 10%.
87 lines
4.5 KiB
LLVM
87 lines
4.5 KiB
LLVM
; RUN: sed -e "s/RETTYPE/void/;s/RETVAL//" %s | llc -mtriple=x86_64-apple-darwin -mcpu=corei7 | FileCheck --check-prefixes=ALL %s
|
|
; RUN: sed -e "s/RETTYPE/i32/;s/RETVAL/undef/" %s | llc -mtriple=x86_64-apple-darwin -mcpu=corei7 | FileCheck --check-prefixes=ALL %s
|
|
; RUN: sed -e "s/RETTYPE/\{i64\,i64\}/;s/RETVAL/undef/" %s | llc -mtriple=x86_64-apple-darwin -mcpu=corei7 | FileCheck --check-prefixes=ALL %s
|
|
;
|
|
; RUN: sed -e "s/RETTYPE/void/;s/RETVAL//" %s | llc -mtriple=x86_64-apple-darwin -mcpu=corei7-avx | FileCheck --check-prefixes=ALL %s
|
|
; RUN: sed -e "s/RETTYPE/i32/;s/RETVAL/undef/" %s | llc -mtriple=x86_64-apple-darwin -mcpu=corei7-avx | FileCheck --check-prefixes=ALL %s
|
|
; RUN: sed -e "s/RETTYPE/\{i64\,i64\}/;s/RETVAL/undef/" %s | llc -mtriple=x86_64-apple-darwin -mcpu=corei7-avx | FileCheck --check-prefixes=ALL %s
|
|
|
|
; We don't need to save registers before using them inside preserve_none function.
|
|
define preserve_nonecc RETTYPE @preserve_nonecc1(i64, i64, double, double) nounwind {
|
|
entry:
|
|
;ALL-LABEL: preserve_nonecc1
|
|
;ALL: pushq %rbp
|
|
;ALL-NEXT: InlineAsm Start
|
|
;ALL-NEXT: InlineAsm End
|
|
;ALL-NEXT: popq %rbp
|
|
;ALL-NEXT: retq
|
|
call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rsi},~{rdi},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{rbp},~{xmm0},~{xmm1},~{xmm2},~{xmm3},~{xmm4},~{xmm5},~{xmm6},~{xmm7},~{xmm8},~{xmm9},~{xmm10},~{xmm11},~{xmm12},~{xmm13},~{xmm14},~{xmm15}"()
|
|
ret RETTYPE RETVAL
|
|
}
|
|
|
|
; When calling a preserve_none function, all live registers must be saved and
|
|
; restored around the function call.
|
|
declare preserve_nonecc RETTYPE @bar(i64, i64, double, double)
|
|
define void @preserve_nonecc2() nounwind {
|
|
entry:
|
|
;ALL-LABEL: preserve_nonecc2
|
|
;ALL: movq %rax
|
|
;ALL: movq %rdx
|
|
;ALL: movq %r11
|
|
;ALL: movaps %xmm2
|
|
;ALL: movaps %xmm3
|
|
;ALL: movaps %xmm4
|
|
;ALL: movaps %xmm5
|
|
;ALL: movaps %xmm6
|
|
;ALL: movaps %xmm7
|
|
;ALL: movaps %xmm8
|
|
;ALL: movaps %xmm9
|
|
;ALL: movaps %xmm10
|
|
;ALL: movaps %xmm11
|
|
;ALL: movaps %xmm12
|
|
;ALL: movaps %xmm13
|
|
;ALL: movaps %xmm14
|
|
;ALL: movaps %xmm15
|
|
;ALL: movq {{.*}}, %rax
|
|
;ALL: movq {{.*}}, %rdx
|
|
;ALL: movq {{.*}}, %r11
|
|
;ALL: movaps {{.*}} %xmm2
|
|
;ALL: movaps {{.*}} %xmm3
|
|
;ALL: movaps {{.*}} %xmm4
|
|
;ALL: movaps {{.*}} %xmm5
|
|
;ALL: movaps {{.*}} %xmm6
|
|
;ALL: movaps {{.*}} %xmm7
|
|
;ALL: movaps {{.*}} %xmm8
|
|
;ALL: movaps {{.*}} %xmm9
|
|
;ALL: movaps {{.*}} %xmm10
|
|
;ALL: movaps {{.*}} %xmm11
|
|
;ALL: movaps {{.*}} %xmm12
|
|
;ALL: movaps {{.*}} %xmm13
|
|
;ALL: movaps {{.*}} %xmm14
|
|
;ALL: movaps {{.*}} %xmm15
|
|
%a0 = call i64 asm sideeffect "", "={rax}"() nounwind
|
|
%a1 = call i64 asm sideeffect "", "={rcx}"() nounwind
|
|
%a2 = call i64 asm sideeffect "", "={rdx}"() nounwind
|
|
%a3 = call i64 asm sideeffect "", "={r8}"() nounwind
|
|
%a4 = call i64 asm sideeffect "", "={r9}"() nounwind
|
|
%a5 = call i64 asm sideeffect "", "={r10}"() nounwind
|
|
%a6 = call i64 asm sideeffect "", "={r11}"() nounwind
|
|
%a10 = call <2 x double> asm sideeffect "", "={xmm2}"() nounwind
|
|
%a11 = call <2 x double> asm sideeffect "", "={xmm3}"() nounwind
|
|
%a12 = call <2 x double> asm sideeffect "", "={xmm4}"() nounwind
|
|
%a13 = call <2 x double> asm sideeffect "", "={xmm5}"() nounwind
|
|
%a14 = call <2 x double> asm sideeffect "", "={xmm6}"() nounwind
|
|
%a15 = call <2 x double> asm sideeffect "", "={xmm7}"() nounwind
|
|
%a16 = call <2 x double> asm sideeffect "", "={xmm8}"() nounwind
|
|
%a17 = call <2 x double> asm sideeffect "", "={xmm9}"() nounwind
|
|
%a18 = call <2 x double> asm sideeffect "", "={xmm10}"() nounwind
|
|
%a19 = call <2 x double> asm sideeffect "", "={xmm11}"() nounwind
|
|
%a20 = call <2 x double> asm sideeffect "", "={xmm12}"() nounwind
|
|
%a21 = call <2 x double> asm sideeffect "", "={xmm13}"() nounwind
|
|
%a22 = call <2 x double> asm sideeffect "", "={xmm14}"() nounwind
|
|
%a23 = call <2 x double> asm sideeffect "", "={xmm15}"() nounwind
|
|
call preserve_nonecc RETTYPE @bar(i64 1, i64 2, double 3.0, double 4.0)
|
|
call void asm sideeffect "", "{rax},{rcx},{rdx},{r8},{r9},{r10},{r11},{xmm2},{xmm3},{xmm4},{xmm5},{xmm6},{xmm7},{xmm8},{xmm9},{xmm10},{xmm11},{xmm12},{xmm13},{xmm14},{xmm15}"(i64 %a0, i64 %a1, i64 %a2, i64 %a3, i64 %a4, i64 %a5, i64 %a6, <2 x double> %a10, <2 x double> %a11, <2 x double> %a12, <2 x double> %a13, <2 x double> %a14, <2 x double> %a15, <2 x double> %a16, <2 x double> %a17, <2 x double> %a18, <2 x double> %a19, <2 x double> %a20, <2 x double> %a21, <2 x double> %a22, <2 x double> %a23)
|
|
ret void
|
|
}
|