[PATCH] D56950: [docs] Prevent O0 optnone for opt input

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: llvm/docs/HowToSubmitABug.rst:87
 If you find that a bug crashes in the optimizer, compile your test-case to a
-``.bc`` file by passing "``-emit-llvm -O0 -c -o foo.bc``".
+``.bc`` file by passing "``-emit-llvm -O0 -Xclang -disable-O0-optnone -c -o foo.bc``".
 Then run:
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smeenai wrote:
> This is definitely over 80 columns, but I'm not sure if we're strict about that in the documentation, and what the best way to split it would be.
> 
> Also, are there any preferences for `-O0 -Xclang -disable-O0-optnone` vs. `-O1 -Xclang -disable-llvm-passes` vs. `-O1 -Xclang -disable-llvm-optzns`?
I think -disable-passes is preferred over -disable-llvm-optzns. That spelling is weird.

Using -O1 -Xclang -disable-llvm-passes is going to more accurately give the IR. There are other differences that clang makes in -O0 other than the obvious optnone.


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https://reviews.llvm.org/D56950