[PATCH] D81198: [docs] Specify rules for updating debug locations

[Adrian Prantl via Phabricator via llvm-commits]

aprantl added inline comments.


================
Comment at: llvm/docs/HowToUpdateDebugInfo.rst:97
+  ``(sext (zext x)) => (zext x)``. The rule for
+  :ref:`preserving locations<WhenToPreserveLocation>` should apply here.
+
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vsk wrote:
> aprantl wrote:
> > I would be curious about an explanation what makes this example different from the fma example above.
> Thanks for pressing on this, it's not terribly clear as-written. How about: "Block-local peepholes which delete redundant instructions, like ``(sext (zext i8 %x to i16) to i32) => (zext i8 %x to i32)``. The inner ``zext`` is modified but remains in its block, so the rule for preserving locations should apply."
sounds good!


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https://reviews.llvm.org/D81198