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[Target/X86] Don't use callee-saved registers in a Win64 tail call on non-Windows. 

Summary:
A small bit that I missed when I updated the X86 backend to account for
the Win64 calling convention on non-Windows. Now we don't use dead
non-volatile registers when emitting a Win64 indirect tail call on
non-Windows.

Should fix PR23710.

Test Plan: Added test for the correct behavior based on the case I posted to PR23710.

Reviewers: rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10258

llvm-svn: 239111
This commit is contained in:
Charles Davis 2015-06-04 22:50:05 +00:00
parent fa5edc5a36
commit da280728b6
2 changed files with 26 additions and 2 deletions
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4
llvm/lib/Target/X86/X86RegisterInfo.cpp
View File

@ -175,12 +175,12 @@ X86RegisterInfo::getPointerRegClass(const MachineFunction &MF,
return &X86::GR64_NOSPRegClass;
return &X86::GR32_NOSPRegClass;
case 2: // Available for tailcall (not callee-saved GPRs).
if (IsWin64)
const Function *F = MF.getFunction();
if (IsWin64 || (F && F->getCallingConv() == CallingConv::X86_64_Win64))
return &X86::GR64_TCW64RegClass;
else if (Is64Bit)
return &X86::GR64_TCRegClass;
const Function *F = MF.getFunction();
bool hasHipeCC = (F ? F->getCallingConv() == CallingConv::HiPE : false);
if (hasHipeCC)
return &X86::GR32RegClass;

24
llvm/test/CodeGen/X86/sibcall-win64.ll
View File

@ -1,7 +1,11 @@
; RUN: llc < %s -mtriple=x86_64-pc-linux | FileCheck %s
declare x86_64_win64cc void @win64_callee(i32)
declare x86_64_win64cc void (i32)* @win64_indirect()
declare x86_64_win64cc void @win64_other(i32)
declare void @sysv_callee(i32)
declare void (i32)* @sysv_indirect()
declare void @sysv_other(i32)
define void @sysv_caller(i32 %p1) {
entry:
@ -40,3 +44,23 @@ define x86_64_win64cc void @win64_matched(i32 %p1) {
; CHECK-LABEL: win64_matched:
; CHECK: jmp win64_callee # TAILCALL
define x86_64_win64cc void @win64_indirect_caller(i32 %p1) {
%1 = call x86_64_win64cc void (i32)* @win64_indirect()
call x86_64_win64cc void @win64_other(i32 0)
tail call x86_64_win64cc void %1(i32 %p1)
ret void
}
; CHECK-LABEL: win64_indirect_caller:
; CHECK: jmpq *%{{rax|rcx|rdx|r8|r9|r11}} # TAILCALL
define void @sysv_indirect_caller(i32 %p1) {
%1 = call void (i32)* @sysv_indirect()
call void @sysv_other(i32 0)
tail call void %1(i32 %p1)
ret void
}
; CHECK-LABEL: sysv_indirect_caller:
; CHECK: jmpq *%{{rax|rcx|rdx|rsi|rdi|r8|r9|r11}} # TAILCALL