Re: [patch, fortran] Handling of .and. and .or. expressions

[Steve Kargl <sgk at troutmask dot apl dot washington dot edu>]

On Thu, Jun 28, 2018 at 07:03:05PM +0200, Jakub Jelinek wrote:
> > In fact, I'll be submitting a bug report for a missed optimization.
> > 
> > subroutine foo(x,y)               subroutine foo(x,y)
> >    real x(10), y(10)                 real x(10), y(10)
> >    y = 0*sin(x)                      y = 0
> > end subroutine foo                end subroutine foo
> > 
> > .L2:                              pxor    %xmm0, %xmm0
> >    call    sinf                   movq    $0, 32(%rsi)
> >    pxor    %xmm1, %xmm1           movups  %xmm0, (%rsi)
> >    mulss   %xmm1, %xmm0           movups  %xmm0, 16(%rsi)
> >    movss   %xmm0, 0(%rbp,%rbx)
> >    addq    $4, %rbx
> >    cmpq    $40, %rbx
> >    jne     .L2
> > 
> > which I'm sure you'll just be thrilled with.
> 
> For floating point, you generally need -ffast-math to be able to
> optimize such computations away, sinf already has const attribute (at least
> in C/C++), so with -ffast-math it is optimized.

Doesn't -ffast-math allow the violaton of the integrity
of parentheses?  That is, it allows more optimizations
that violate the standard.

-- 
Steve