[PATCH] D16434: Fix ARM load/store opt live reg computing

[Weiming Zhao via llvm-commits]

weimingz created this revision.
weimingz added a reviewer: t.p.northover.
weimingz added a subscriber: llvm-commits.
weimingz set the repository for this revision to rL LLVM.
Herald added subscribers: rengolin, aemerson.

Shrink-wrap may hoist the restore of LR from exiting BB. So when
moveLiveRegsBefore() computes free regs, it will not count LR as live.
This patch marks LR could be clobbed when it encounters a bx_ret inst.


Repository:
  rL LLVM

http://reviews.llvm.org/D16434

Files:
  lib/Target/ARM/ARMLoadStoreOptimizer.cpp

Index: lib/Target/ARM/ARMLoadStoreOptimizer.cpp
===================================================================
--- lib/Target/ARM/ARMLoadStoreOptimizer.cpp
+++ lib/Target/ARM/ARMLoadStoreOptimizer.cpp
@@ -560,6 +560,9 @@
   while (LiveRegPos != Before) {
     --LiveRegPos;
     LiveRegs.stepBackward(*LiveRegPos);
+    if (LiveRegPos->getOpcode() == ARM::tBX_RET ||
+        LiveRegPos->getOpcode() == ARM::tBX_RET)
+      LiveRegs.addReg(ARM::LR);
   }
 }
 


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