Re: Compiler Optimisation?

jfc@mit.edu (John F Carr)
13 Dec 1998 13:58:17 -0500

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From: jfc@mit.edu (John F Carr)
Newsgroups: comp.lang.ada,comp.compilers
Date: 13 Dec 1998 13:58:17 -0500
Organization: Massachvsetts Institvte of Technology
References: 98-12-010 98-12-020
Keywords: optimize

Thomas W. Christopher <tc@charlie.cns.iit.edu> wrote:
>As I recall, he found that "folding," performing constant arithmetic at
>compile time, not only makes the compiled code run faster, but also the
>compiler.


On AIX 3.1, I found that "gcc -O -c" was often faster than "gcc -c"
because the assembler was so slow. Apparently IBM didn't use it much
internally (or adb, the assembly-level debugger which was also slow
and buggy). It was faster for gcc to optimize the code than it was
for as to process the extra instructions in unoptimized code.


--
        John Carr (jfc@mit.edu)


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