--- Comment #9 from ubizjak at gmail dot com 2009-06-25 09:03 ---
*** This bug has been marked as a duplicate of 21920 ***
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ubizjak at gmail dot com changed:
What|Removed |Added
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--- Comment #8 from hjl dot tools at gmail dot com 2009-06-24 13:09 ---
(In reply to comment #6)
> _mm_load_sd( (const doubleA*)(from) )
>
> does not work because the prototype of _mm_load_sd does not have a type
> with the may-alias attribute, so it gets stripped again.
>
I think mov
--- Comment #7 from ubizjak at gmail dot com 2009-06-24 11:57 ---
Adding x86 intrinsic expert...
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ubizjak at gmail dot com changed:
What|Removed |Added
--- Comment #6 from rguenth at gcc dot gnu dot org 2009-06-24 11:25 ---
_mm_load_sd( (const doubleA*)(from) )
does not work because the prototype of _mm_load_sd does not have a type
with the may-alias attribute, so it gets stripped again.
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http://gcc.gnu.org/bugzilla/show_bug.cgi
--- Comment #5 from rguenth at gcc dot gnu dot org 2009-06-24 11:23 ---
There are aliasing issues with your code / the intrinsics implementation:
float data[4] = {1, 2, 3, 4};
...
r = _mm_castpd_ps(_mm_load_sd((double*)(from)));
ends up loading from float data via a pointer to doub
--- Comment #4 from gael dot guennebaud at gmail dot com 2009-06-24 11:12
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some additional info:
- compiling with -fno-strict-aliasing fix the issue, so perhaps this is not a
real bug but a feature ?
- on the other hand using the may_alias type attribute for casting does not
help:
--- Comment #3 from gael dot guennebaud at gmail dot com 2009-06-24 10:53
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There is a compilable example attached to comment #1.
Furthermore, I can reproduce the problem with gcc 4.1.3, 4.2.4, 4.3.2, and
4.4.0, so I don't think it is a duplicate of PR40141.
FYI, in the meantime I
--- Comment #2 from rguenth at gcc dot gnu dot org 2009-06-24 09:48 ---
I can't verify it (you do not provide complete source that can be compiled),
but I think this is a duplicate of PR40141 which is fixed in GCC 4.4.
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rguenth at gcc dot gnu dot org changed:
What|R
--- Comment #1 from gael dot guennebaud at gmail dot com 2009-06-24 08:07
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Created an attachment (id=18055)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18055&action=view)
a complete example showing the problem
usage:
Works:
g++ -O3 instr_dependency.cpp -o instr_dependency
