[PATCH] D31908: [AntiDepBreaker] Don't rename callee saved register restore instruction

[Guozhi Wei via Phabricator via llvm-commits]

Carrot created this revision.

Current AntiDepBreaker implementation can rename callee saved register restore instruction, and then callee saved register contain garbage value after return.

We should not rename callee saved register restore instruction.


https://reviews.llvm.org/D31908

Files:
  lib/CodeGen/AggressiveAntiDepBreaker.cpp


Index: lib/CodeGen/AggressiveAntiDepBreaker.cpp
===================================================================
--- lib/CodeGen/AggressiveAntiDepBreaker.cpp
+++ lib/CodeGen/AggressiveAntiDepBreaker.cpp
@@ -858,6 +858,10 @@
           // the use if required to break an earlier antidep.
           DEBUG(dbgs() << " (passthru)\n");
           continue;
+        } else if ((RegClassInfo.getLastCalleeSavedAlias(AntiDepReg) != 0) &&
+                   (RegRefs.count(AntiDepReg) == 1)) {
+          // Don't rename callee saved register restore instruction.
+          continue;
         } else {
           // No anti-dep breaking for implicit deps
           MachineOperand *AntiDepOp = MI.findRegisterDefOperand(AntiDepReg);


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