From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Wed, 15 Jul 2009 22:32:11 +0000 (+0000)
Subject: Fix bug in RegScavenger::scavengeRegister().
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=72fbc3d9d260e061bdee07059fcd63772c714091;p=oota-llvm.git

Fix bug in RegScavenger::scavengeRegister().

Reserved registers are not candidates for scavenging, and they were removed
from the candidate list like this:

CreateRegClassMask(RC, Candidates);
Candidates ^= ReservedRegs;

However, when there are reserved registers outside RC, this causes invalid
bits to be set in Candidates.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75847 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/RegisterScavenging.cpp b/lib/CodeGen/RegisterScavenging.cpp
index 84cff8d5d88..98f485045f6 100644
--- a/lib/CodeGen/RegisterScavenging.cpp
+++ b/lib/CodeGen/RegisterScavenging.cpp
@@ -426,7 +426,7 @@ unsigned RegScavenger::scavengeRegister(const TargetRegisterClass *RC,
   // Mask off the registers which are not in the TargetRegisterClass.
   BitVector Candidates(NumPhysRegs, false);
   CreateRegClassMask(RC, Candidates);
-  Candidates ^= ReservedRegs;  // Do not include reserved registers.
+  Candidates ^= ReservedRegs & Candidates; // Do not include reserved registers.
 
   // Exclude all the registers being used by the instruction.
   for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {