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Downwards growing stack allocation order reverses relative offsets 

llvm-svn: 111673
This commit is contained in:
Jim Grosbach 2010-08-20 20:25:31 +00:00
parent 9b0b6d45d2
commit 7648a21152
1 changed files with 10 additions and 1 deletions
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11
llvm/lib/CodeGen/LocalStackSlotAllocation.cpp
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@ -174,6 +174,7 @@ static inline bool
lookupCandidateBaseReg(const SmallVector<std::pair<unsigned, int64_t>, 8> &Regs,
std::pair<unsigned, int64_t> &RegOffset,
int64_t LocalFrameOffset,
bool StackGrowsDown,
const MachineInstr *MI,
const TargetRegisterInfo *TRI) {
unsigned e = Regs.size();
@ -182,6 +183,8 @@ lookupCandidateBaseReg(const SmallVector<std::pair<unsigned, int64_t>, 8> &Regs,
// Check if the relative offset from the where the base register references
// to the target address is in range for the instruction.
int64_t Offset = LocalFrameOffset - RegOffset.second;
if (StackGrowsDown)
Offset = -Offset;
if (TRI->isFrameOffsetLegal(MI, Offset))
return true;
}
@ -199,6 +202,9 @@ bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
MachineFrameInfo *MFI = Fn.getFrameInfo();
const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo();
bool StackGrowsDown =
TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
for (MachineFunction::iterator BB = Fn.begin(),
E = Fn.end(); BB != E; ++BB) {
@ -245,12 +251,15 @@ bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
// register.
std::pair<unsigned, int64_t> RegOffset;
if (lookupCandidateBaseReg(BaseRegisters, RegOffset,
LocalOffsets[FrameIdx], MI, TRI)) {
LocalOffsets[FrameIdx],
StackGrowsDown, MI, TRI)) {
DEBUG(dbgs() << " Reusing base register " <<
RegOffset.first << "\n");
// We found a register to reuse.
BaseReg = RegOffset.first;
Offset = LocalOffsets[FrameIdx] - RegOffset.second;
if (StackGrowsDown)
Offset = -Offset;
} else {
// No previously defined register was in range, so create a
// new one.