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* [Bug middle-end/27321] New: Compare against constant infinity fails with IBM long double format
@ 2006-04-26 2:17 dvdfrdmn at users dot sf dot net
2006-04-26 2:27 ` [Bug middle-end/27321] " pinskia at gcc dot gnu dot org
2006-04-30 7:33 ` pinskia at gcc dot gnu dot org
0 siblings, 2 replies; 4+ messages in thread
From: dvdfrdmn at users dot sf dot net @ 2006-04-26 2:17 UTC (permalink / raw)
To: gcc-bugs
Test code:
long double x = __builtin_infl();
int main() {
int r = x == __builtin_infl();
return r ? 0 : 1;
}
Commands to reproduce:
gcc -mlong-double-128 tc.c
./a.out && echo ok || echo fail
No problem with -mlong-double-64.
Cause:
GCC first transforms (x == infinity) to (x > long_double_max_val).
The maximum value returned by real_maxval is encoded as infinity due
to rounding in encode_ibm_extended. This does not happen with the
LDBL_MAX declared in system headers because one of the bits is
cleared.
Potential fix:
--- real.c.orig 2005-09-19 12:56:24.000000000 -0400
+++ real.c 2006-04-25 21:18:32.000000000 -0400
@@ -2205,6 +2205,8 @@ real_maxval (REAL_VALUE_TYPE *r, int sig
np2 = SIGNIFICAND_BITS - fmt->p * fmt->log2_b;
memset (r->sig, -1, SIGSZ * sizeof (unsigned long));
clear_significand_below (r, np2);
+ if (REAL_MODE_FORMAT_COMPOSITE_P (mode))
+ clear_significand_bit (r, SIGNIFICAND_BITS - fmt->pnan - 1);
}
--
Summary: Compare against constant infinity fails with IBM long
double format
Product: gcc
Version: 4.0.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dvdfrdmn at users dot sf dot net
GCC target triplet: powerpc-apple-darwin8
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27321
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug middle-end/27321] Compare against constant infinity fails with IBM long double format 2006-04-26 2:17 [Bug middle-end/27321] New: Compare against constant infinity fails with IBM long double format dvdfrdmn at users dot sf dot net @ 2006-04-26 2:27 ` pinskia at gcc dot gnu dot org 2006-04-30 7:33 ` pinskia at gcc dot gnu dot org 1 sibling, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu dot org @ 2006-04-26 2:27 UTC (permalink / raw) To: gcc-bugs ------- Comment #1 from pinskia at gcc dot gnu dot org 2006-04-26 02:27 ------- This works in the mainline. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27321 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/27321] Compare against constant infinity fails with IBM long double format 2006-04-26 2:17 [Bug middle-end/27321] New: Compare against constant infinity fails with IBM long double format dvdfrdmn at users dot sf dot net 2006-04-26 2:27 ` [Bug middle-end/27321] " pinskia at gcc dot gnu dot org @ 2006-04-30 7:33 ` pinskia at gcc dot gnu dot org 1 sibling, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu dot org @ 2006-04-30 7:33 UTC (permalink / raw) To: gcc-bugs ------- Comment #2 from pinskia at gcc dot gnu dot org 2006-04-30 07:33 ------- Actually I am wrong in saying it worked. I usually forget to test the return value as I assume people use abort to signal a failure. -- pinskia at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Ever Confirmed|0 |1 GCC target triplet|powerpc-apple-darwin8 |powerpc*-*-* Keywords| |wrong-code Last reconfirmed|0000-00-00 00:00:00 |2006-04-30 07:33:00 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27321 ^ permalink raw reply [flat|nested] 4+ messages in thread
[parent not found: <bug-27321-4@http.gcc.gnu.org/bugzilla/>]
* [Bug middle-end/27321] Compare against constant infinity fails with IBM long double format [not found] <bug-27321-4@http.gcc.gnu.org/bugzilla/> @ 2012-03-02 19:26 ` bernhard.kaindl at thalesgroup dot com 0 siblings, 0 replies; 4+ messages in thread From: bernhard.kaindl at thalesgroup dot com @ 2012-03-02 19:26 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27321 Bernhard Kaindl <bernhard.kaindl at thalesgroup dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bernhard.kaindl at | |thalesgroup dot com --- Comment #3 from Bernhard Kaindl <bernhard.kaindl at thalesgroup dot com> 2012-03-02 19:25:55 UTC --- Verification using powerpc-linux-gcc-4.4.6 (--host=i686-linux): Testcase works, it seems this may be fixed. Suggest closing after soon 6 years. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-03-02 19:26 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2006-04-26 2:17 [Bug middle-end/27321] New: Compare against constant infinity fails with IBM long double format dvdfrdmn at users dot sf dot net
2006-04-26 2:27 ` [Bug middle-end/27321] " pinskia at gcc dot gnu dot org
2006-04-30 7:33 ` pinskia at gcc dot gnu dot org
[not found] <bug-27321-4@http.gcc.gnu.org/bugzilla/>
2012-03-02 19:26 ` bernhard.kaindl at thalesgroup dot com
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