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* Re: optimization/10252: __builtin_constant_p() returns TRUE for non-constant expression
@ 2003-03-31 1:16 rth
0 siblings, 0 replies; 3+ messages in thread
From: rth @ 2003-03-31 1:16 UTC (permalink / raw)
To: davidm, gcc-bugs, gcc-prs, nobody, rth
Synopsis: __builtin_constant_p() returns TRUE for non-constant expression
Responsible-Changed-From-To: unassigned->rth
Responsible-Changed-By: rth
Responsible-Changed-When: Sun Mar 30 23:22:40 2003
Responsible-Changed-Why:
.
State-Changed-From-To: open->closed
State-Changed-By: rth
State-Changed-When: Sun Mar 30 23:22:40 2003
State-Changed-Why:
http://gcc.gnu.org/ml/gcc-patches/2003-03/msg02497.html
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10252
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: optimization/10252: __builtin_constant_p() returns TRUE for non-constant expression
@ 2003-03-28 8:46 Alan Modra
0 siblings, 0 replies; 3+ messages in thread
From: Alan Modra @ 2003-03-28 8:46 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR optimization/10252; it has been noted by GNATS.
From: Alan Modra <amodra@bigpond.net.au>
To: davidm@hpl.hp.com
Cc: gcc-gnats@gcc.gnu.org, rth@redhat.com
Subject: Re: optimization/10252: __builtin_constant_p() returns TRUE for non-constant expression
Date: Fri, 28 Mar 2003 19:02:05 +1030
Same thing happens on powerpc64-linux. __bad_stuff will never be
executed, so looks like dead code elimination isn't working properly.
14: 38 00 00 00 li r0,0
18: 2f 80 00 00 cmpwi cr7,r0,0
1c: 40 9e 00 14 bne- cr7,30 <.foo+0x30>
[snip]
30: 48 00 00 01 bl 30 <.foo+0x30>
30: R_PPC64_REL24 .__bad_stuff
--
Alan Modra
IBM OzLabs - Linux Technology Centre
^ permalink raw reply [flat|nested] 3+ messages in thread
* optimization/10252: __builtin_constant_p() returns TRUE for non-constant expression
@ 2003-03-28 7:36 davidm
0 siblings, 0 replies; 3+ messages in thread
From: davidm @ 2003-03-28 7:36 UTC (permalink / raw)
To: gcc-gnats; +Cc: rth
>Number: 10252
>Category: optimization
>Synopsis: __builtin_constant_p() returns TRUE for non-constant expression
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: wrong-code
>Submitter-Id: net
>Arrival-Date: Fri Mar 28 07:36:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator: David Mosberger
>Release: gcc version 3.4 20030327 (experimental)
>Organization:
>Environment:
IA-64 Linux
>Description:
The attached test-program demonstrates a case where GCC
thinks a non-constant expression is constant. When compiled
with -O2, the resulting object file will have an undefined
reference to __bad_stuff(). The problem doesn't show with
lower optimization levels.
>How-To-Repeat:
gcc -Wall -c -O2 sem.i
nm sem.o |grep bad
U __bad_stuff
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2003-03-31 1:16 optimization/10252: __builtin_constant_p() returns TRUE for non-constant expression rth
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2003-03-28 8:46 Alan Modra
2003-03-28 7:36 davidm
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