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Re: [PATCH] Use malloca instead alloca
On 01/12/2013 02:24 PM, Rich Felker wrote:
>> gcc does not optimize alloca
>> > well so type[constant] is faster than alloca(constant). This is bug in
>> > gcc and can be fixed.
> No, this _cannot_ be fixed. If any non-static-sized objects
Surely GCC can be fixed so that a function that does this first:
char *p = alloca (100);
is executed with code that's no slower than if the function had
done this first:
char buf[100];
char *p = buf;
Currently, GCC doesn't do this optimization, but I don't see any
reason why it couldn't.
There are other optimizations involving alloca (constant) that
GCC couldn't do, but the ones that OndÅej are talking about
seem doable.