llvm/test/CodeGen/X86/swiftself.ll
Matthias Braun cd45ee92d7 X86: Use a callee save register for the swiftself parameter.
It is very likely that the swiftself parameter is alive throughout most
functions function so putting it into a callee save register should
avoid spills for the callers with only a minimum amount of extra spills
in the callees.

Currently the generated code is correct but unnecessarily spills and
reloads arguments passed in callee save registers, I will address this
in upcoming patches.

This also adds a missing check that for tail calls the preserved value
of the caller must be the same as the callees parameter.

Differential Revision: http://reviews.llvm.org/D18902

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266252 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-13 21:43:21 +00:00

63 lines
2.0 KiB
LLVM

; RUN: llc -verify-machineinstrs -mtriple=x86_64-unknown-unknown -o - %s | FileCheck --check-prefix=CHECK --check-prefix=OPT %s
; RUN: llc -O0 -verify-machineinstrs -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
; Parameter with swiftself should be allocated to r13.
; CHECK-LABEL: swiftself_param:
; CHECK: movq %r13, %rax
define i8 *@swiftself_param(i8* swiftself %addr0) {
ret i8 *%addr0
}
; Check that r13 is used to pass a swiftself argument.
; CHECK-LABEL: call_swiftself:
; CHECK: movq %rdi, %r13
; CHECK: callq {{_?}}swiftself_param
define i8 *@call_swiftself(i8* %arg) {
%res = call i8 *@swiftself_param(i8* swiftself %arg)
ret i8 *%res
}
; r13 should be saved by the callee even if used for swiftself
; CHECK-LABEL: swiftself_clobber:
; CHECK: pushq %r13
; ...
; CHECK: popq %r13
define i8 *@swiftself_clobber(i8* swiftself %addr0) {
call void asm sideeffect "nop", "~{r13}"()
ret i8 *%addr0
}
; Demonstrate that we do not need any movs when calling multiple functions
; with swiftself argument.
; CHECK-LABEL: swiftself_passthrough:
; OPT-NOT: mov{{.*}}r13
; OPT: callq {{_?}}swiftself_param
; OPT-NOT: mov{{.*}}r13
; OPT-NEXT: callq {{_?}}swiftself_param
define void @swiftself_passthrough(i8* swiftself %addr0) {
call i8 *@swiftself_param(i8* swiftself %addr0)
call i8 *@swiftself_param(i8* swiftself %addr0)
ret void
}
; We can use a tail call if the callee swiftself is the same as the caller one.
; CHECK-LABEL: swiftself_tail:
; OPT: jmp {{_?}}swiftself_param
; OPT-NOT: ret
define i8* @swiftself_tail(i8* swiftself %addr0) {
call void asm sideeffect "", "~{r13}"()
%res = tail call i8* @swiftself_param(i8* swiftself %addr0)
ret i8* %res
}
; We can not use a tail call if the callee swiftself is not the same as the
; caller one.
; CHECK-LABEL: swiftself_notail:
; CHECK: movq %rdi, %r13
; CHECK: callq {{_?}}swiftself_param
; CHECK: retq
define i8* @swiftself_notail(i8* swiftself %addr0, i8* %addr1) nounwind {
%res = tail call i8* @swiftself_param(i8* swiftself %addr1)
ret i8* %res
}