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[Issue 21490] Optimizer can add SSE integer multiply for machines less than SSE4.1 which do not have it
[Issue 21490] Front end detection logic for SSE4.1 is failing when using -O
Dec 19, 2020
Walter Bright
Dec 20, 2020
Walter Bright
Dec 20, 2020
Walter Bright
Dec 20, 2020
Dlang Bot
Dec 20, 2020
Dlang Bot
December 19, 2020
Gravatar of Walter BrightPosted by Walter BrightReply
Walter Bright
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https://issues.dlang.org/show_bug.cgi?id=21490

Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |SIMD

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December 20, 2020
Gravatar of Walter BrightPosted by Walter BrightReply
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https://issues.dlang.org/show_bug.cgi?id=21490

--- Comment #1 from Walter Bright <bugzilla@digitalmars.com> ---
Test case clipped from dmd/test/runnable/testxmm.d:

-------
import core.simd;

void test2e()
{
    int4 v1, v2 = 1, v3 = 1;
    v1 = v2 + v3;
    static if (__traits(compiles, { v1 = v2 * v3; })) // SSE4.1
        v1 = v2 * v3;
}

int main() { test2e(); return 0; }
------

This will seg fault on illegal PMULLD instruction if running on a machine without SSE4.1

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December 20, 2020
Gravatar of Walter BrightPosted by Walter BrightReply
Walter Bright
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https://issues.dlang.org/show_bug.cgi?id=21490

Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Front end detection logic   |Optimizer can add SSE
                   |for SSE4.1 is failing when  |integer multiply for
                   |using -O                    |machines less than SSE4.1
                   |                            |which do not have it

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December 20, 2020
Gravatar of Dlang BotPosted by Dlang BotReply
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https://issues.dlang.org/show_bug.cgi?id=21490

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull

--- Comment #2 from Dlang Bot <dlang-bot@dlang.rocks> ---
@WalterBright created dlang/dmd pull request #12038 "fix Issue 21490 - Optimizer can add SSE integer multiply for machines…" fixing this issue:

- fix Issue 21490 - Optimizer can add SSE integer multiply for machines less than SSE4.1 which do not have it

https://github.com/dlang/dmd/pull/12038

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December 20, 2020
Gravatar of Dlang BotPosted by Dlang BotReply
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https://issues.dlang.org/show_bug.cgi?id=21490

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/dmd pull request #12038 "fix Issue 21490 - Optimizer can add SSE integer multiply for machines…" was merged into master:

- c3a3456f248784e029af056b4d0a383e9c29974a by Walter Bright:
  fix Issue 21490 - Optimizer can add SSE integer multiply for machines less
than SSE4.1 which do not have it

https://github.com/dlang/dmd/pull/12038

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