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Re: [gfortran,patch] Make MIN and MAX handle NaNs correctly (PR32048)


pinskia@gmail.com wrote:
On 7/28/07, Tim Prince <tprince@myrealbox.com> wrote:
FX Coudert wrote:
Does this affect minval() and maxval() intrinsics?  Up to now, they
performed as well as equivalent C code with icpc, better than g++, but
not as well as ifort.  I suppose it removes the prospect of vectorizing
code with min() and max(), unless that will be enabled with -ffast-math.

Actually the G++ code should be better on the trunk than before. If it is not, can you file a new bug?


I did find several cases where g++ x86-64 performance improved greatly in the last month, but this is not one of them.
I didn't find anything clear to complain about. g++ is generating a lot of useless (on Core 2) p2align, but that does not correlate with performance. g++ uses minps memory to register operations, while gfortran loads each operand first. This looks like a way for g++ to favor reduced code size over performance (somewhat contradictory, after consuming space with p2align). It might be better to unroll less and pre-load the operands. I didn't think this is worth a PR, when I have plenty of long-standing PRs.



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