[PATCH] D95578: [Docs] Update HowToSubmitABug
Fangrui Song via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Jan 27 16:43:16 PST 2021
MaskRay added a subscriber: nickdesaulniers.
MaskRay added a comment.
@nickdesaulniers
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Comment at: llvm/docs/HowToSubmitABug.rst:92
If you find that a bug crashes in the optimizer, compile your test-case to a
``.bc`` file by passing "``-emit-llvm -O1 -Xclang -disable-llvm-passes -c -o
+foo.bc``". The ``-O1`` is important because ``-O0`` adds the ``optnone``
----------------
Worth mentioning that `-Xclang -disable-O0-optnone` can disable emitted `optnone`.
================
Comment at: llvm/docs/HowToSubmitABug.rst:125
+If none of the above work, you can get the IR before a crash by running the
+``opt`` command with the ``--print-before-all --print-module-scope`` flags to
+dump the IR before every pass. Be warned that this is very verbose.
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I only use `--print-module-scope` with `-filter-print-funcs`...
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Comment at: llvm/docs/HowToSubmitABug.rst:164
+reading a variable before it is defined). In particular, check to see if the
+program is clean under various sanitizers and `valgrind
+<http://valgrind.org/>`_. Many "LLVM bugs" that we have chased down ended up
----------------
Perhaps also: `-fsanitize=address,undefined` && `-fsanitize=memory`
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rG LLVM Github Monorepo
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https://reviews.llvm.org/D95578
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