Verify liveness is working

Author: hiraditya

llvm/lib/Target/RISCV/RISCVLiveVariables.cpp

@@ -320,6 +320,13 @@ void RISCVLiveVariables::computeGlobalLiveness(MachineFunction &MF) {
     const MachineBasicBlock &EntryBB = MF.front();
     NumLiveRegsAtEntry += BlockLiveness[&EntryBB].LiveIn.size();
   }
+
+  for (auto &BB : MF) {
+    auto &computedLivein = BlockLiveness[&BB].LiveIn;
+    for (auto &LI : BB.getLiveIns()) {
+      assert(0 && computedLivein.count(LI.PhysReg));
+    }
+  }
 }
 
 bool RISCVLiveVariables::isLiveAt(Register Reg,

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

@@ -564,7 +564,6 @@ void RISCVPassConfig::addPreEmitPass() {
   addPass(createRISCVIndirectBranchTrackingPass());
   addPass(&BranchRelaxationPassID);
   addPass(createRISCVMakeCompressibleOptPass());
-  addPass(createRISCVLiveVariablesPass());
 }
 
 void RISCVPassConfig::addPreEmitPass2() {
@@ -597,7 +596,6 @@ void RISCVPassConfig::addMachineSSAOptimization() {
   TargetPassConfig::addMachineSSAOptimization();
 
   if (TM->getTargetTriple().isRISCV64()) {
-    addPass(createRISCVLiveVariablesPass());
     addPass(createRISCVOptWInstrsPass());
   }
 }
@@ -629,6 +627,8 @@ void RISCVPassConfig::addPostRegAlloc() {
   if (TM->getOptLevel() != CodeGenOptLevel::None &&
       EnableRedundantCopyElimination)
     addPass(createRISCVRedundantCopyEliminationPass());
+
+  addPass(createRISCVLiveVariablesPass());
 }
 
 bool RISCVPassConfig::addILPOpts() {