Add an assertion to catch register of illegal class.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48751 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index 2713771..6925de3 100644
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -886,6 +886,7 @@
// Scan for the first available register.
TargetRegisterClass::iterator I = RC->allocation_order_begin(*mf_);
TargetRegisterClass::iterator E = RC->allocation_order_end(*mf_);
+ assert(I != E && "No allocatable register in this register class!");
for (; I != E; ++I)
if (prt_->isRegAvail(*I)) {
FreeReg = *I;