[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

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMBaseRegisterInfo.h b/llvm/lib/Target/ARM/ARMBaseRegisterInfo.h
index af2b9a4c469..fdc1ef9432c 100644
--- a/llvm/lib/Target/ARM/ARMBaseRegisterInfo.h
+++ b/llvm/lib/Target/ARM/ARMBaseRegisterInfo.h
@@ -143,7 +143,7 @@ public:
                                     int64_t Offset) const override;
   void resolveFrameIndex(MachineInstr &MI, unsigned BaseReg,
                          int64_t Offset) const override;
-  bool isFrameOffsetLegal(const MachineInstr *MI,
+  bool isFrameOffsetLegal(const MachineInstr *MI, unsigned BaseReg,
                           int64_t Offset) const override;
 
   bool cannotEliminateFrame(const MachineFunction &MF) const;