[llvm] [AMDGPU] Clear dbg info on CFG intrinsic due to incorrect behaviour in gdb. (PR #83010)

[Emma Pilkington via llvm-commits]

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@@ -336,8 +342,9 @@ bool SIAnnotateControlFlow::closeControlFlow(BasicBlock *BB) {
       // Split edge to make Def dominate Use
       FirstInsertionPt = SplitEdge(DefBB, BB, DT, LI)->getFirstInsertionPt();
     }
-    IRBuilder<>(FirstInsertionPt->getParent(), FirstInsertionPt)
-        .CreateCall(EndCf, {Exec});
+    IRBuilder<> IRB(FirstInsertionPt->getParent(), FirstInsertionPt);
+    IRB.SetCurrentDebugLocation(DebugLoc());
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epilk wrote:

This is the only DebugLoc that is causing GDB test failures, where control flow joins in the 'Flow' block. Could you remove the other changes in this PR? I think the other debug locations should all be correct.

A comment might be nice here too, maybe something like: "StructurizeCFG 'Flow' blocks have debug locations from the condition, for now just avoid copying these DebugLocs so that stepping out of the then/else block in a debugger doesn't step to the condition."?

https://github.com/llvm/llvm-project/pull/83010