Disable shrink-wrap for Thumb1
Summary: In ARMConstantIslandPass, which runs after Shrink Wrap pass, long jumps will be fixed up as BL (tBfar) which depends on spilling LR in epilogue. However, shrink-wrap may remove the LR, which causes issues when the function returns.
Reviewers: qcolombet, rengolin
Subscribers: aemerson, rengolin
Differential Revision: http://reviews.llvm.org/D15984
llvm-svn: 257187
diff --git a/llvm/lib/Target/ARM/Thumb1FrameLowering.h b/llvm/lib/Target/ARM/Thumb1FrameLowering.h
index 812f983..27faac6 100644
--- a/llvm/lib/Target/ARM/Thumb1FrameLowering.h
+++ b/llvm/lib/Target/ARM/Thumb1FrameLowering.h
@@ -53,6 +53,11 @@
/// \p MBB will be correctly handled by the target.
bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
+ /// Disable shrink wrap as tBfar/BL will be used to adjust for long jumps.
+ bool enableShrinkWrapping(const MachineFunction &MF) const override {
+ return false;
+ }
+
private:
/// Check if the frame lowering of \p MF needs a special fixup
/// code sequence for the epilogue.