Don't reserve R31 on PPC64 unless the frame pointer is needed

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177379 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2013-03-19 08:09:38 +00:00
parent d37c8568e6
commit 54e57f8cb7
2 changed files with 18 additions and 4 deletions

View File

@ -117,16 +117,15 @@ BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
}
// On PPC64, r13 is the thread pointer. Never allocate this register.
// Note that this is over conservative, as it also prevents allocation of R31
// when the FP is not needed.
if (Subtarget.isPPC64()) {
Reserved.set(PPC::R13);
Reserved.set(PPC::R31);
Reserved.set(PPC::X0);
Reserved.set(PPC::X1);
Reserved.set(PPC::X13);
Reserved.set(PPC::X31);
if (PPCFI->needsFP(MF))
Reserved.set(PPC::X31);
// The 64-bit SVR4 ABI reserves r2 for the TOC pointer.
if (Subtarget.isSVR4ABI()) {

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@ -0,0 +1,15 @@
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=g4 | FileCheck %s
target datalayout = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f128:64:128-n32"
define i64 @foo(i64 %a) nounwind {
entry:
call void asm sideeffect "", "~{r0},~{r3},~{r4},~{r5},~{r6},~{r7},~{r8},~{r9},~{r10},~{r11},~{r12},~{r14},~{r15},~{r16},~{r17},~{r18},~{r19},~{r20},~{r21},~{r22},~{r23},~{r24},~{r25},~{r26},~{r27},~{r28},~{r29},~{r30}"() nounwind
br label %return
; CHECK: @foo
; CHECK: mr 31, 3
return: ; preds = %entry
ret i64 %a
}