replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

PowerPC: Slight cleanup of getReservedRegs(); NFC 

Change getReservedRegs() to not mark a register as reserved and then
revert that decision in some cases. Motivated by the discussion in
https://reviews.llvm.org/D29056

llvm-svn: 293073
This commit is contained in:
Matthias Braun 2017-01-25 17:12:10 +00:00
parent fd7165364b
commit aeb8e33968
1 changed files with 10 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
View File

@ -234,30 +234,21 @@ BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
// The SVR4 ABI reserves r2 and r13
if (Subtarget.isSVR4ABI()) {
markSuperRegs(Reserved, PPC::R2); // System-reserved register
// We only reserve r2 if we need to use the TOC pointer. If we have no
// explicit uses of the TOC pointer (meaning we're a leaf function with
// no constant-pool loads, etc.) and we have no potential uses inside an
// inline asm block, then we can treat r2 has an ordinary callee-saved
// register.
const PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
if (!TM.isPPC64() || FuncInfo->usesTOCBasePtr() || MF.hasInlineAsm())
markSuperRegs(Reserved, PPC::R2); // System-reserved register
markSuperRegs(Reserved, PPC::R13); // Small Data Area pointer register
}
if (TM.isPPC64()) {
// On PPC64, r13 is the thread pointer. Never allocate this register.
// On PPC64, r13 is the thread pointer. Never allocate this register.
if (TM.isPPC64())
markSuperRegs(Reserved, PPC::R13);
// The 64-bit SVR4 ABI reserves r2 for the TOC pointer.
if (Subtarget.isSVR4ABI()) {
// We only reserve r2 if we need to use the TOC pointer. If we have no
// explicit uses of the TOC pointer (meaning we're a leaf function with
// no constant-pool loads, etc.) and we have no potential uses inside an
// inline asm block, then we can treat r2 has an ordinary callee-saved
// register.
const PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
if (!FuncInfo->usesTOCBasePtr() && !MF.hasInlineAsm()) {
for (MCSuperRegIterator Super(PPC::R2, this, true); Super.isValid();
++Super)
Reserved.reset(*Super);
}
}
}
if (TFI->needsFP(MF))
markSuperRegs(Reserved, PPC::R31);