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[ARM] Fix handling of thumb1 out-of-range frame offsets

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LocalStackSlotPass assumes that isFrameOffsetLegal doesn't change its
answer when the base register changes. Unfortunately this isn't true
in thumb1, where SP-based loads allow a larger offset than
non-SP-based loads, and this causes the base register reuse code to
generate instructions that are unencodable, causing an assertion
failure. 

Solve this by adding a BaseReg parameter to isFrameOffsetLegal, which
ARMBaseRegisterInfo can then make use of to give the correct answer. 

Differential Revision: http://reviews.llvm.org/D8419


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232825 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
John Brawn
2015-03-20 17:20:07 +00:00
parent 45f61bfec3
commit 151a5da534
9 changed files with 59 additions and 19 deletions
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12
lib/CodeGen/LocalStackSlotAllocation.cpp
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@ -252,7 +252,8 @@ void LocalStackSlotPass::calculateFrameObjectOffsets(MachineFunction &Fn) {
}
static inline bool
lookupCandidateBaseReg(int64_t BaseOffset,
lookupCandidateBaseReg(unsigned BaseReg,
int64_t BaseOffset,
int64_t FrameSizeAdjust,
int64_t LocalFrameOffset,
const MachineInstr *MI,
@ -260,7 +261,7 @@ lookupCandidateBaseReg(int64_t BaseOffset,
// 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 = FrameSizeAdjust + LocalFrameOffset - BaseOffset;
return TRI->isFrameOffsetLegal(MI, Offset);
return TRI->isFrameOffsetLegal(MI, BaseReg, Offset);
}
bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
@ -362,8 +363,9 @@ bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
// instruction itself will be taken into account by the target,
// so we don't have to adjust for it here when reusing a base
// register.
if (UsedBaseReg && lookupCandidateBaseReg(BaseOffset, FrameSizeAdjust,
LocalOffset, MI, TRI)) {
if (UsedBaseReg && lookupCandidateBaseReg(BaseReg, BaseOffset,
FrameSizeAdjust, LocalOffset, MI,
TRI)) {
DEBUG(dbgs() << " Reusing base register " << BaseReg << "\n");
// We found a register to reuse.
Offset = FrameSizeAdjust + LocalOffset - BaseOffset;
@ -382,7 +384,7 @@ bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
// then don't bother creating it.
if (ref + 1 >= e ||
!lookupCandidateBaseReg(
BaseOffset, FrameSizeAdjust,
BaseReg, BaseOffset, FrameSizeAdjust,
FrameReferenceInsns[ref + 1].getLocalOffset(),
FrameReferenceInsns[ref + 1].getMachineInstr(), TRI)) {
BaseOffset = PrevBaseOffset;