Fix PR2757. Ignore liveinterval register allocation preference if the preference register is not in the right register class. This can happen due to sub-register coalescing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56006 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index 91dda77..2cfa755 100644
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -1036,7 +1036,7 @@
// If copy coalescer has assigned a "preferred" register, check if it's
// available first.
if (cur->preference) {
- if (prt_->isRegAvail(cur->preference)) {
+ if (prt_->isRegAvail(cur->preference) && RC->contains(cur->preference)) {
DOUT << "\t\tassigned the preferred register: "
<< tri_->getName(cur->preference) << "\n";
return cur->preference;