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From: "bernd.edlinger at hotmail dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/58970] [4.7/4.8/4.9 Regression] internal compiler error: in get_bit_range, at expr.c:4562
Date: Tue, 05 Nov 2013 08:28:00 -0000 [thread overview]
Message-ID: <bug-58970-4-tZ2EylIWuF@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-58970-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58970
--- Comment #23 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
hmm...
all examples I can see, where bitpos is negative,
or less than the representative's bitoffset with offset=NULL,
are just blandtly invalid.
The only valid example would be
struct S { unsigned char s : 1; };
void function(struct S *p)
{
p[-1].s = 0;
}
However this one is gimplified to
D.1590 = p + -1;
D.1590->s = 0;
no ARRAY_REFs at all, never.
Handling all that negative bitoffsets seems to be
a bit too much complication just to generate
valid code for invalid C.
At least returning negative bitoffset could be easily
avoided in get_inner_reference:
--- expr.c.jj 2013-10-31 14:57:05.000000000 +0100
+++ expr.c 2013-11-05 09:24:39.821624212 +0100
@@ -6708,7 +6708,7 @@
tem = tem.sext (TYPE_PRECISION (sizetype));
tem = tem.lshift (BITS_PER_UNIT == 8 ? 3 : exact_log2 (BITS_PER_UNIT));
tem += bit_offset;
- if (tem.fits_shwi ())
+ if (tem.fits_shwi () && !tem.is_negative ())
{
*pbitpos = tem.to_shwi ();
*poffset = offset = NULL_TREE;
next prev parent reply other threads:[~2013-11-05 8:28 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-02 10:16 [Bug middle-end/58970] New: " jan.smets@alcatel-lucent.com
2013-11-02 10:17 ` [Bug middle-end/58970] " jan.smets@alcatel-lucent.com
2013-11-02 13:38 ` [Bug middle-end/58970] [4.7/4.8/4.9 Regression] " mpolacek at gcc dot gnu.org
2013-11-03 19:16 ` bernd.edlinger at hotmail dot de
2013-11-04 0:56 ` jan.smets@alcatel-lucent.com
2013-11-04 8:41 ` jakub at gcc dot gnu.org
2013-11-04 9:00 ` bernd.edlinger at hotmail dot de
2013-11-04 9:31 ` jakub at gcc dot gnu.org
2013-11-04 9:32 ` jakub at gcc dot gnu.org
2013-11-04 9:54 ` bernd.edlinger at hotmail dot de
2013-11-04 10:01 ` jakub at gcc dot gnu.org
2013-11-04 10:07 ` bernd.edlinger at hotmail dot de
2013-11-04 10:12 ` jakub at gcc dot gnu.org
2013-11-04 10:32 ` bernd.edlinger at hotmail dot de
2013-11-04 11:07 ` bernd.edlinger at hotmail dot de
2013-11-04 11:30 ` jakub at gcc dot gnu.org
2013-11-04 11:46 ` bernd.edlinger at hotmail dot de
2013-11-04 12:10 ` bernd.edlinger at hotmail dot de
2013-11-04 12:15 ` jakub at gcc dot gnu.org
2013-11-04 14:28 ` rguenth at gcc dot gnu.org
2013-11-04 16:02 ` jakub at gcc dot gnu.org
2013-11-04 17:55 ` ebotcazou at gcc dot gnu.org
2013-11-05 8:28 ` bernd.edlinger at hotmail dot de [this message]
2013-11-05 19:37 ` bernd.edlinger at hotmail dot de
2013-11-06 7:50 ` jakub at gcc dot gnu.org
2013-11-06 14:11 ` jan.smets@alcatel-lucent.com
2013-11-11 7:57 ` jakub at gcc dot gnu.org
2013-11-11 9:41 ` jan.smets@alcatel-lucent.com
2013-11-19 13:33 ` [Bug middle-end/58970] [4.7 " rguenth at gcc dot gnu.org
2014-04-23 12:39 ` jan.smets@alcatel-lucent.com
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