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digitalmars.D.bugs - [Issue 8060] New: xmmstore cannot allocate store for optimized operation that uses int and floats

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=8060

           Summary: xmmstore cannot allocate store for optimized operation
                    that uses int and floats
           Product: D
           Version: D1 & D2
          Platform: x86_64
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: fawzi gmx.ch


--- Comment #0 from Fawzi Mohamed <fawzi gmx.ch> 2012-05-07 13:51:45 PDT ---
float invSqrt(float x) {
    union fi {
    float f;
    int i;
    }
    fi v;
    float xhalf = 0.5f * x;
    v.f = x;
    v.i = 0x5f375a86 - (v.i >> 1);
    float y = x * v.f;
    float z = y*(1.5f - xhalf * y * y);
    return z;
}

or

float invSqrt(float x) {
    float xhalf = 0.5f * x;
    int i = *cast(int*)&x;
    i = 0x5f375a86 - (i >> 1);
    x = *cast(float*)&i;
    x = x*(1.5f - xhalf * x * x);
    return x;
}

fails with error

tym = xa
Internal error: ../ztc/cgxmm.c 567

when compiled with dmd 1.074 or 2.059 with -O

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--- Comment #1 from Fawzi Mohamed <fawzi gmx.ch> 2012-05-07 13:54:15 PDT ---
well probably the optimizer should not expect such a thing to be possible.

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Fawzi Mohamed <fawzi gmx.ch> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |regression


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prev sibling next sibling parent d-bugmail puremagic.com writes:
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Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clugdbug yahoo.com.au


--- Comment #2 from Don <clugdbug yahoo.com.au> 2012-05-14 00:59:21 PDT ---
Reduced test case. The float needs to be a parameter (not a local variable).

float bug8060(float x) {
    int i = *cast(int*)&x;
    ++i;
    return *cast(float*)&i;
}

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--- Comment #4 from github-bugzilla puremagic.com 2012-05-18 23:03:08 PDT ---
Commit pushed to dmd-1.x at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/cb946cd258a186f09cbaa303d1ded96a8ebb095d
fix Issue 8060 - xmmstore cannot allocate store for optimized operation that
uses int and floats

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prev sibling parent d-bugmail puremagic.com writes:
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Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla digitalmars.com
         Resolution|                            |FIXED


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