Don't bother spilling before a return
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103831 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocFast.cpp b/lib/CodeGen/RegAllocFast.cpp
index 651f010..2a66cb1 100644
--- a/lib/CodeGen/RegAllocFast.cpp
+++ b/lib/CodeGen/RegAllocFast.cpp
@@ -768,11 +768,20 @@
// Spill all physical registers holding virtual registers now.
atEndOfBlock = true;
- DEBUG(dbgs() << "Killing live registers at end of block.\n");
MachineBasicBlock::iterator MI = MBB.getFirstTerminator();
- for (LiveRegMap::iterator i = LiveVirtRegs.begin(), e = LiveVirtRegs.end();
- i != e; ++i)
- spillVirtReg(MBB, MI, i, true);
+ if (MI != MBB.end() && MI->getDesc().isReturn()) {
+ // This is a return block, kill all virtual registers.
+ DEBUG(dbgs() << "Killing live registers at end of return block.\n");
+ for (LiveRegMap::iterator i = LiveVirtRegs.begin(), e = LiveVirtRegs.end();
+ i != e; ++i)
+ killVirtReg(i);
+ } else {
+ // This is a normal block, spill any dirty virtregs.
+ DEBUG(dbgs() << "Spilling live registers at end of block.\n");
+ for (LiveRegMap::iterator i = LiveVirtRegs.begin(), e = LiveVirtRegs.end();
+ i != e; ++i)
+ spillVirtReg(MBB, MI, i, true);
+ }
LiveVirtRegs.clear();
// Erase all the coalesced copies. We are delaying it until now because