RegAllocPBQP: Do not assign reserved physical register
(0) RegAllocPBQP: Since getRawAllocationOrder() may return a collection that includes reserved physical registers, iterate to find an un-reserved physical register.
(1) VirtRegMap: Enforce the invariant: "no reserved physical registers" in assignVirt2Phys(). Previously, this was checked only after the fact in VirtRegRewriter::rewrite.
(2) MachineVerifier: updated the test per MatzeB's review.
(3) +testcase
Patch by Nick Johnson<Nicholas.Paul.Johnson@deshawresearch.com>!
Differential Revision: https://reviews.llvm.org/D33947
llvm-svn: 305016
diff --git a/llvm/lib/CodeGen/RegAllocPBQP.cpp b/llvm/lib/CodeGen/RegAllocPBQP.cpp
index f3ef50f..e3baff4 100644
--- a/llvm/lib/CodeGen/RegAllocPBQP.cpp
+++ b/llvm/lib/CodeGen/RegAllocPBQP.cpp
@@ -738,7 +738,15 @@
if (PReg == 0) {
const TargetRegisterClass &RC = *MRI.getRegClass(LI.reg);
- PReg = RC.getRawAllocationOrder(MF).front();
+ const ArrayRef<MCPhysReg> RawPRegOrder = RC.getRawAllocationOrder(MF);
+ for (unsigned CandidateReg : RawPRegOrder) {
+ if (!VRM.getRegInfo().isReserved(CandidateReg)) {
+ PReg = CandidateReg;
+ break;
+ }
+ }
+ assert(PReg &&
+ "No un-reserved physical registers in this register class");
}
VRM.assignVirt2Phys(LI.reg, PReg);