Clear virtual registers after they are no longer referenced.
Passes after RegAlloc should be able to rely on MRI->getNumVirtRegs() == 0.
This makes sharing code for pre/postRA passes more robust.
Now, to check if a pass is running before the RA pipeline begins, use MRI->isSSA().
To check if a pass is running after the RA pipeline ends, use !MRI->getNumVirtRegs().
PEI resets virtual regs when it's done scavenging.
PTX will either have to provide its own PEI pass or assign physregs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151032 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocFast.cpp b/lib/CodeGen/RegAllocFast.cpp
index 6d7b5f4..b8b05a9 100644
--- a/lib/CodeGen/RegAllocFast.cpp
+++ b/lib/CodeGen/RegAllocFast.cpp
@@ -1104,6 +1104,10 @@
while (*Defs)
MRI->setPhysRegUsed(*Defs++);
+ // All machine operands and other references to virtual registers have been
+ // replaced. Remove the virtual registers.
+ MRI->clearVirtRegs();
+
SkippedInstrs.clear();
StackSlotForVirtReg.clear();
LiveDbgValueMap.clear();