[CSInfo][TailDuplicator] Delete the call site info when removing dead MBBs

[djtodoro]

Summary

Needed for the D73534. All tests pass after applying the D73534 again.

This is splitting of the D74614, but it should be revisited once again.

[vsk]

LGTM with a nit. I believe this supersedes https://reviews.llvm.org/D74614?

llvm/lib/CodeGen/TailDuplicator.cpp

1023

Just so that the history makes sense, could you add -debug-entry-values to a TailDuplicator test in this patch, then remove it in D73534?

[djtodoro]

I believe this supersedes https://reviews.llvm.org/D74614?

I think I can come up with a test case describing we need the D74614 as well (but modified, that is why I marked that as not finished).

llvm/lib/CodeGen/TailDuplicator.cpp

1023

Sure, I’ll add that.

[djtodoro]

• Add the '-debug-entry-values' into the tail-dup test

llvm/lib/CodeGen/TailDuplicator.cpp

 /// Remove the specified dead machine basic block from the function, updating
 /// the CFG.
 void TailDuplicator::removeDeadBlock(
     MachineBasicBlock *MBB,
     function_ref<void(MachineBasicBlock *)> *RemovalCallback) {
   assert(MBB->pred_empty() && "MBB must be dead!");
   LLVM_DEBUG(dbgs() << "\nRemoving MBB: " << *MBB);
 
+  MachineFunction *MF = MBB->getParent();
+  // Update the call site info.
+  std::for_each(MBB->begin(), MBB->end(), [MF](const MachineInstr &MI) {
+    if (MI.isCandidateForCallSiteEntry())
+      MF->eraseCallSiteInfo(&MI);
+  });
+
   if (RemovalCallback)
     (*RemovalCallback)(MBB);
 
   // Remove all successors.
   while (!MBB->succ_empty())
     MBB->removeSuccessor(MBB->succ_end() - 1);
 
   // Remove the block.
   MBB->eraseFromParent();
 }

llvm/test/CodeGen/X86/tail-dup-repeat.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -debug-entry-values | FileCheck %s
 
 ; Function Attrs: uwtable
 ; When tail-duplicating during placement, we work backward from blocks with
 ; multiple successors. In this case, the block dup1 gets duplicated into dup2
 ; and if.then64, and then the block dup2 gets duplicated into land.lhs.true
 ; and if.end70
 
 define void @repeated_tail_dup(i1 %a1, i1 %a2, i32* %a4, i32* %a5, i8* %a6, i32 %a7) #0 align 2 {