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[Bug fortran/31139] sum(w_re(1:nn,1)*fi(i(1:nn, ii))) up to 3.5x slower than C version
- From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 12 Mar 2007 05:37:53 -0000
- Subject: [Bug fortran/31139] sum(w_re(1:nn,1)*fi(i(1:nn, ii))) up to 3.5x slower than C version
- References: <bug-31139-13404@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #4 from pinskia at gcc dot gnu dot org 2007-03-12 05:37 -------
> The hand-made SSE version (USE_VECTORS) crashes here for -m32
Because well complex(8)'s alignment is the same as double which means it is
only 8 byte aligned and not 16 byte aligned, it is just magical that the SSE
case works for -m64 also.
I am thinking about declaring this bug as invalid as right now the C testcase
is not even closely related to the Fortran case.
Can someone try instead of doing "__real__ a += w[j ] * __real__ mfi[*index
];" Use "a+= xxx* yyy" and also use -std=c99 to get the correct multiplication?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31139