GNU bug report logs - #35562
"varset" bytecode inline path is never taken

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Simon Frankau <sgf <at> arbitrary.name>
To: bug-gnu-emacs <at> gnu.org
Subject: "varset" bytecode inline path is never taken
Date: Sat, 4 May 2019 14:27:23 +0100

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While reading the source, I noticed in bytecode.c that:

    /* Inline the most common case.  */
    if (SYMBOLP (sym)
&& !EQ (val, Qunbound)
&& *!XSYMBOL (sym)->u.s.redirect*
&& !SYMBOL_TRAPPED_WRITE_P (sym))
      SET_SYMBOL_VAL (XSYMBOL (sym), val);

should be:

    /* Inline the most common case.  */
    if (SYMBOLP (sym)
&& !EQ (val, Qunbound)
&& *XSYMBOL (sym)->u.s.redirect == SYMBOL_PLAINVAL*
&& !SYMBOL_TRAPPED_WRITE_P (sym))
      SET_SYMBOL_VAL (XSYMBOL (sym), val);

As it is, the inline case is never run, since "redirect" is always non-zero.

Since I'm new to emacs internals, I don't know how to benchmark to work out
if this makes a noticable performance difference. :)

Thanks,
Simon.

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