[llvm] r337735 - Fix RegScavenger::unprocess

[David Greene via llvm-commits]

Author: greened
Date: Mon Jul 23 13:23:50 2018
New Revision: 337735

URL: http://llvm.org/viewvc/llvm-project?rev=337735&view=rev
Log:
Fix RegScavenger::unprocess

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.

Differential Revision: https://reviews.llvm.org/D42200


Modified:
    llvm/trunk/lib/CodeGen/RegisterScavenging.cpp

Modified: llvm/trunk/lib/CodeGen/RegisterScavenging.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegisterScavenging.cpp?rev=337735&r1=337734&r2=337735&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegisterScavenging.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegisterScavenging.cpp Mon Jul 23 13:23:50 2018
@@ -162,8 +162,8 @@ void RegScavenger::unprocess() {
     determineKillsAndDefs();
 
     // Commit the changes.
-    setUsed(KillRegUnits);
     setUnused(DefRegUnits);
+    setUsed(KillRegUnits);
   }
 
   if (MBBI == MBB->begin()) {