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Re: Matching regex case-sensitively in C strings?


From: Robert Pluim
Subject: Re: Matching regex case-sensitively in C strings?
Date: Thu, 10 Nov 2022 12:35:56 +0100

>>>>> On Thu, 10 Nov 2022 13:18:56 +0200, Eli Zaretskii <eliz@gnu.org> said:

    >> From: Mattias Engdegård <mattiase@acm.org>
    >> Date: Thu, 10 Nov 2022 10:52:40 +0100
    >> Cc: casouri@gmail.com, emacs-devel@gnu.org
    >> 
    >> 9 nov. 2022 kl. 14.06 skrev Eli Zaretskii <eliz@gnu.org>:
    >> 
    >> >> You are right to worry about it, but there is actually no need for
    >> >> concern here: it's a tail call (and the extra argument is last) so
    >> >> it should compile to an unconditional jump (and setting a register).
    >> > 
    >> > That's not what I see here, even with -O2.
    >> 
    >> Trying to read your mind, are you using 32-bit x86? Even that
    >> shouldn't be disastrous; it's just some stack manipulation. Hardly
    >> noticeable given that it's a regexp match that comes next.

    Eli> I agree that the effect is probably minuscule, but it's still there.
    Eli> And on some architectures it could be more than that.

    Eli> Why not have two separate functions for these two jobs?  The code is
    Eli> short, and some duplication is not an issue in this case.

Or one generic function and two #defines that pass in the appropriate
canonicalize table value.

Robert
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