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Improve time-equal-p etc. performance

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* src/timefns.c (time_cmp): Return EMACS_INT, not int; no need to
change callers.  Compare (X . Z) to (Y . Z) quickly if X and Y are
fixnums.
This commit is contained in:
Paul Eggert 2022-08-01 00:38:32 -07:00
parent 0a4477415c
commit 24e1123241
1 changed files with 7 additions and 1 deletions
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8
src/timefns.c
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@ -1192,7 +1192,7 @@ For example, nil stands for the current time. */)
/* Return negative, 0, positive if A < B, A == B, A > B respectively.
A and B should be Lisp time values. */
static int
static EMACS_INT
time_cmp (Lisp_Object a, Lisp_Object b)
{
/* Compare nil to nil correctly, and handle other eq values quicker
@ -1201,6 +1201,12 @@ time_cmp (Lisp_Object a, Lisp_Object b)
if (BASE_EQ (a, b))
return 0;
/* Compare (X . Z) to (Y . Z) quickly if X and Y are fixnums.
Do not inspect Z, as it is OK to not signal if A and B are invalid. */
if (FASTER_TIMEFNS && CONSP (a) && CONSP (b) && BASE_EQ (XCDR (a), XCDR (b))
&& FIXNUMP (XCAR (a)) && FIXNUMP (XCAR (b)))
return XFIXNUM (XCAR (a)) - XFIXNUM (XCAR (b));
/* Compare (ATICKS . AZ) to (BTICKS . BHZ) by comparing
ATICKS * BHZ to BTICKS * AHZ. */
struct lisp_time ta = lisp_time_struct (a, 0);