[llvm] [AMDGPU][FixIrreducible][UnifyLoopExits] Support callbr with inline-asm (PR #149308)

[Sameer Sahasrabuddhe via llvm-commits]

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@@ -342,3 +345,55 @@ std::pair<BasicBlock *, bool> ControlFlowHub::finalize(
 
   return {FirstGuardBlock, true};
 }
+
+BasicBlock *ControlFlowHub::createCallBrTarget(
+    CallBrInst *CallBr, BasicBlock *Succ, unsigned SuccIdx, bool AttachToCallBr,
+    CycleInfo *CI, DomTreeUpdater *DTU, LoopInfo *LI) {
+  BasicBlock *CallBrBlock = CallBr->getParent();
+  BasicBlock *CallBrTarget =
+      BasicBlock::Create(CallBrBlock->getContext(),
+                         CallBrBlock->getName() + ".target." + Succ->getName(),
+                         CallBrBlock->getParent());
+  // Rewire control flow from callbr to the new target block.
+  Succ->replacePhiUsesWith(CallBrBlock, CallBrTarget);
+  CallBr->setSuccessor(SuccIdx, CallBrTarget);
+  // Jump from the new target block to the original successor.
+  BranchInst::Create(Succ, CallBrTarget);
+  if (LI) {
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ssahasra wrote:

If you make this is a separate function say `updateLI()`, that will allow you to eliminate `AddToLoop` using early returns. And that function won't need to be a class member. I personally feel that will improve readability here.

https://github.com/llvm/llvm-project/pull/149308