[llvm] [DebugInfo][RemoveDIs] Support maintaining DPValues in CodeGenPrepare (PR #73660)

[Orlando Cazalet-Hyams via llvm-commits]

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@@ -2234,7 +2239,9 @@ static bool despeculateCountZeros(IntrinsicInst *CountZeros,
   // Create another block after the count zero intrinsic. A PHI will be added
   // in this block to select the result of the intrinsic or the bit-width
   // constant if the input to the intrinsic is zero.
-  BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(CountZeros));
+  BasicBlock::iterator SplitPt = std::next(BasicBlock::iterator(CountZeros));
+  // Any debug-info after CountZeros should not be included.
+  SplitPt.setHeadBit(true); // coveredy by Transforms/CodeGenPrepare/X86/cttz-ctlz.ll
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OCHyams wrote:

Did you intend to leave the test coverage comments in? There's are a few others scattered about too.

https://github.com/llvm/llvm-project/pull/73660