[PATCH] D42200: Fix RegScavenger::unprocess

[David Greene via Phabricator via llvm-commits]

greened created this revision.
greened added reviewers: MatzeB, silviu.baranga, kparzysz.
Herald added a subscriber: llvm-commits.

RegScavenger::unprocess walks backward, so it should undo the effects of defs before undoing effects of kills.  Previously it did things in the opposite order, leaving a register apparently unused (dead) in the case where an instruction both used (killed) and defined a register.


Repository:
  rL LLVM

https://reviews.llvm.org/D42200

Files:
  lib/CodeGen/RegisterScavenging.cpp


Index: lib/CodeGen/RegisterScavenging.cpp
===================================================================
--- lib/CodeGen/RegisterScavenging.cpp
+++ lib/CodeGen/RegisterScavenging.cpp
@@ -162,8 +162,8 @@
     determineKillsAndDefs();
 
     // Commit the changes.
-    setUsed(KillRegUnits);
     setUnused(DefRegUnits);
+    setUsed(KillRegUnits);
   }
 
   if (MBBI == MBB->begin()) {


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