[ARM] Fix handling of thumb1 out-of-range frame offsets
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
llvm-svn: 232825
diff --git a/llvm/lib/CodeGen/LocalStackSlotAllocation.cpp b/llvm/lib/CodeGen/LocalStackSlotAllocation.cpp
index e8bf687..8378429 100644
--- a/llvm/lib/CodeGen/LocalStackSlotAllocation.cpp
+++ b/llvm/lib/CodeGen/LocalStackSlotAllocation.cpp
@@ -252,7 +252,8 @@
}
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 @@
// 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 @@
// 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 @@
// 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;