Re: Can compilers do this?

[l117593@cliffy.lfwc.lockheed.com (Cordes MJ)]

BWBurnsed (bwburnsed@aol.com) wrote:

   <snip>

: Also, suppose Y and X are floating point variables, and M and B are 
: CONSTANT floating point variables (not named numbers) initialized to
: 1.0  and  0.0  respectively. If one writes

:      Y := M * X  +  B ;

: can (and will) any compiler reduce this to

:      Y := X ;

I can't say that all compilers will perform this optimization, but
the Tartan VMS/1750 Ada compiler does (at its standard optimization
level).

We have seen cases where some compilers will perform the optimization
if the statement is written as:

     Y := (M * X) + B;

but it will not perform the optimization when written as you 
originally posted.

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Michael J Cordes
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