On Thursday 04 January 2007 18:37, Linus Torvalds wrote:
> With 7+ million lines of C code and headers, I'm not interested in
> compilers that read the letter of the law. We don't want some really
> clever code generation that gets us .5% on some unrealistic load. We want
> good _solid_ code generation that does the obvious thing.
>
> Compiler writers seem to seldom even realize this. A lot of commercial
> code gets shipped with basically no optimizations at all (or with specific
> optimizations turned off), because people want to ship what they debug and
> work with.
I'd say "care about obvious, safe optimizations which we still not do".
I want this:
char v[4];
...
memcmp(v, "abcd", 4) == 0
compile to single cmpl on i386. This (gcc 4.1.1) is ridiculous:
.LC0:
.string "abcd"
.text
...
pushl $4
pushl $.LC0
pushl $v
call memcmp
addl $12, %esp
testl %eax, %eax
There are tons of examples where you can improve code generation.
--
vda
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