[RISCV] Defer creating RISCVInsertVSETVLI to avoid leak with -stop-after (#92303)

As noted in
#91440 (comment),
if the pass pipeline stops early because of -stop-after any allocated
passes added with insertPass will not be freed if they haven't already
been added.

This was showing up as a failure on the address sanitizer buildbots. We
can fix it by instead passing the pass ID instead so that allocation is
deferred.

Author: lukel97

llvm/lib/Target/RISCV/RISCV.h

@@ -60,6 +60,7 @@ void initializeRISCVExpandAtomicPseudoPass(PassRegistry &);
 
 FunctionPass *createRISCVInsertVSETVLIPass();
 void initializeRISCVInsertVSETVLIPass(PassRegistry &);
+extern char &RISCVInsertVSETVLIID;
 
 FunctionPass *createRISCVCoalesceVSETVLIPass();
 void initializeRISCVCoalesceVSETVLIPass(PassRegistry &);

llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp

@@ -868,6 +868,7 @@ class RISCVCoalesceVSETVLI : public MachineFunctionPass {
 } // end anonymous namespace
 
 char RISCVInsertVSETVLI::ID = 0;
+char &llvm::RISCVInsertVSETVLIID = RISCVInsertVSETVLI::ID;
 
 INITIALIZE_PASS(RISCVInsertVSETVLI, DEBUG_TYPE, RISCV_INSERT_VSETVLI_NAME,
                 false, false)

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

@@ -548,9 +548,9 @@ void RISCVPassConfig::addPreRegAlloc() {
   // Run RISCVInsertVSETVLI after PHI elimination. On O1 and above do it after
   // register coalescing so needVSETVLIPHI doesn't need to look through COPYs.
   if (TM->getOptLevel() == CodeGenOptLevel::None)
-    insertPass(&PHIEliminationID, createRISCVInsertVSETVLIPass());
+    insertPass(&PHIEliminationID, &RISCVInsertVSETVLIID);
   else
-    insertPass(&RegisterCoalescerID, createRISCVInsertVSETVLIPass());
+    insertPass(&RegisterCoalescerID, &RISCVInsertVSETVLIID);
 }
 
 void RISCVPassConfig::addFastRegAlloc() {