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From: James Addison <jay@jp-hosting.net>
To: gcc@gcc.gnu.org
Subject: avx512erintrin.h: uninitialized variable warning (optimized build)
Date: Thu, 12 Jan 2023 00:26:45 +0000	[thread overview]
Message-ID: <CALDQ5NxWOswUk+40zoyPckK4oR8PMpi+_bRcTSYQgnU+6WiaXw@mail.gmail.com> (raw)

Hi,

During GCC 12.2.0 compilation of a file that includes[1] immintrin.h
with both code-optimization and uninitialized-variable-warnings
enabled, a warning is emitted:

    /usr/lib/gcc/x86_64-linux-gnu/12/include/avx512erintrin.h:55:20:
warning: ‘__W’ is used uninitialized [-Wuninitialized]

The minimal repro compilation command appears to be:

    gcc -O -Wuninitialized -mavx512er -mavx512pf
./numpy/distutils/checks/cpu_avx512_knl.c

My question is: does the warning indicate a possible bug that should
be reported, or is there a reason that the relevant code[2] does not
initialize the variable (for example, for performance reasons)?

Thank you,
James

[1] - https://github.com/numpy/numpy/blob/bb2769e12a8646f3d63097e9464592aa6e20058d/numpy/distutils/checks/cpu_avx512_knl.c#L14

[2] - https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/i386/avx512erintrin.h;h=6b3b679a17675612f45a1090f227012b80b871a6#l54

             reply	other threads:[~2023-01-12  0:26 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-12  0:26 James Addison [this message]
2023-01-12  6:51 ` Sam James
2023-01-12 11:30   ` James Addison

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