From: Chad Rosier <mcrosier@codeaurora.org>
Date: Mon, 6 Jul 2015 14:46:34 +0000 (+0000)
Subject: Fix a bug in the A57FPLoadBalancing register tracking/scavenger.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ac244651b2cce9746fab546ea71b6183b70ab589;p=oota-llvm.git

Fix a bug in the A57FPLoadBalancing register tracking/scavenger.

The code in AArch64A57FPLoadBalancing::scavengeRegister() to handle dead defs
was not correctly handling aliased registers.  E.g. if the dead def was of D2,
then S2 was not being marked as unavailable, so it could potentially be used
across a live-range in which it would be clobbered.

Patch by Geoff Berry <gberry@codeaurora.org>!
Phabricator: http://reviews.llvm.org/D10900


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241449 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp b/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp
index bffd9e6e8c7..9d6dbd641a1 100644
--- a/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp
+++ b/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp
@@ -510,9 +510,17 @@ int AArch64A57FPLoadBalancing::scavengeRegister(Chain *G, Color C,
       if (J.isRegMask())
         AvailableRegs.clearBitsNotInMask(J.getRegMask());
 
-      if (J.isReg() && J.isDef() && AvailableRegs[J.getReg()]) {
-        assert(J.isDead() && "Non-dead def should have been removed by now!");
-        AvailableRegs.reset(J.getReg());
+      if (J.isReg() && J.isDef()) {
+        MCRegAliasIterator AI(J.getReg(), TRI, /*IncludeSelf=*/true);
+        if (J.isDead())
+          for (; AI.isValid(); ++AI)
+            AvailableRegs.reset(*AI);
+#ifndef NDEBUG
+        else
+          for (; AI.isValid(); ++AI)
+            assert(!AvailableRegs[*AI] &&
+                   "Non-dead def should have been removed by now!");
+#endif
       }
     }
   }