From 03cf7fe31be5964707a54ed82969b9c181f8dd99 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Fri, 16 Mar 2012 02:57:35 -0700 Subject: [PATCH] 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. --- ChangeLog | 5 +++++ time/mktime.c | 8 +++++--- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/ChangeLog b/ChangeLog index 5b99dac31f2..b5cf3768578 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,10 @@ 2012-05-23 Paul Eggert + 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. diff --git a/time/mktime.c b/time/mktime.c index 6d4db69da23..5144987708d 100644 --- a/time/mktime.c +++ b/time/mktime.c @@ -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, -- 2.39.5