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mktime: check signed shifts on long_int and time_t, too

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* time/mktime.c (SHR): Check that shifts work as desired
on the types long_int and time_t too, as SHR is used on
such types.
This commit is contained in:
Paul Eggert 2012-03-16 02:57:35 -07:00
parent f04dfbc244
commit 03cf7fe31b
2 changed files with 10 additions and 3 deletions
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5
ChangeLog
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@ -1,5 +1,10 @@
2012-05-23 Paul Eggert <eggert@cs.ucla.edu>
mktime: check signed shifts on long_int and time_t, too
* time/mktime.c (SHR): Check that shifts work as desired
on the types long_int and time_t too, as SHR is used on
such types.
mktime: do not assume 'long' is wide enough
* time/mktime.c (verify): Move decl up.
(long_int): New type.

8
time/mktime.c
View file

@ -89,9 +89,11 @@ verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
implementations (e.g., UNICOS 9.0 on a Cray Y-MP EL) don't shift
right in the usual way when A < 0, so SHR falls back on division if
ordinary A >> B doesn't seem to be the usual signed shift. */
#define SHR(a, b) \
(-1 >> 1 == -1 \
? (a) >> (b) \
#define SHR(a, b) \
((-1 >> 1 == -1 \
&& (long_int) -1 >> 1 == -1 \
&& ((time_t) -1 >> 1 == -1 || ! TYPE_SIGNED (time_t))) \
? (a) >> (b) \
: (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))
/* The extra casts in the following macros work around compiler bugs,