If an interval is being undone clear its preference as well since the source interval may have been undone as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43670 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index 2d675b0..98b62ce 100644
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -209,7 +209,7 @@
/// different register classes or because the coalescer was overly
/// conservative.
unsigned RALinScan::attemptTrivialCoalescing(LiveInterval &cur, unsigned Reg) {
- if (cur.preference && cur.preference == Reg || !cur.containsOneValue())
+ if ((cur.preference && cur.preference == Reg) || !cur.containsOneValue())
return Reg;
VNInfo *vni = cur.getValNumInfo(0);
@@ -791,6 +791,11 @@
vrm_->clearVirt(i->reg);
unhandled_.push(i);
}
+
+ // It interval has a preference, it must be defined by a copy. Clear the
+ // preference now since the source interval allocation may have been undone
+ // as well.
+ i->preference = 0;
}
// Rewind the iterators in the active, inactive, and fixed lists back to the