[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-03-29 20:03 --- This most likely can be reproduced on ia64 too and other targets where alignment is needed for some loads. The tree which we produce looks like: : if (p->c[0] != 0) goto ; else goto ; :; D.1133 = *((unsigned char *) p + 5B); p = p + 1B; if (D.1133 != 0) goto ; else goto ; -- What|Removed |Added Summary|[4.0 regression] ivopts |[4.0/4.1 regression] ivopts |produces code that generates|produces code that generates |"unaligned access exception"|"unaligned access exception" Target Milestone|--- |4.0.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From falk at debian dot org 2005-03-29 20:23 --- (In reply to comment #6) > This most likely can be reproduced on ia64 too and other targets where alignment is needed for some > loads. I cannot reproduce it with -mcpu=ev56, though, so maybe it needs a plaform that does not have narrow loads (do we have any other except alphaev4?). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From rakdver at atrey dot karlin dot mff dot cuni dot cz 2005-03-29 20:47 --- Subject: Re: [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception" > This most likely can be reproduced on ia64 too and other targets where > alignment is needed for some > loads. > > The tree which we produce looks like: > : > if (p->c[0] != 0) goto ; else goto ; > > :; > D.1133 = *((unsigned char *) p + 5B); > p = p + 1B; > if (D.1133 != 0) goto ; else goto ; The problem seems to be that the expansion assumes that p must be aligned. Which seems to be reasonable. I will try making ivopts produce all pointer ivs in (void *) type, that should hopefully help. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From rakdver at atrey dot karlin dot mff dot cuni
dot cz 2005-03-29 21:09 ---
Subject: Re: [4.0/4.1 regression] ivopts produces code that generates
"unaligned access exception"
> > This most likely can be reproduced on ia64 too and other targets where
> > alignment is needed for some
> > loads.
> >
> > The tree which we produce looks like:
> > :
> > if (p->c[0] != 0) goto ; else goto ;
> >
> > :;
> > D.1133 = *((unsigned char *) p + 5B);
> > p = p + 1B;
> > if (D.1133 != 0) goto ; else goto ;
>
> The problem seems to be that the expansion assumes that p must be
> aligned. Which seems to be reasonable. I will try making ivopts
> produce all pointer ivs in (void *) type, that should hopefully
> help.
This patch should fix the problem (I have looked on crosscompiler
output only, so I am not entirely sure yet).
Index: tree-ssa-loop-ivopts.c
===
RCS file: /cvs/gcc/gcc/gcc/tree-ssa-loop-ivopts.c,v
retrieving revision 2.54
diff -c -3 -p -r2.54 tree-ssa-loop-ivopts.c
*** tree-ssa-loop-ivopts.c 22 Mar 2005 22:08:53 - 2.54
--- tree-ssa-loop-ivopts.c 29 Mar 2005 21:07:33 -
*** strip_offset (tree expr, bool inside_add
*** 1840,1845
--- 1840,1861
return fold_convert (orig_type, expr);
}
+ /* Returns variant of TYPE that can be used as base for different uses.
+For integer types, we return unsigned variant of the type, which
+avoids problems with overflows. For pointer types, we return void *. */
+
+ static tree
+ generic_type_for (tree type)
+ {
+ if (POINTER_TYPE_P (type))
+ return ptr_type_node;
+
+ if (TYPE_UNSIGNED (type))
+ return type;
+
+ return unsigned_type_for (type);
+ }
+
/* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and
position to POS. If USE is not NULL, the candidate is set as related to
it. If both BASE and STEP are NULL, we add a pseudocandidate for the
*** add_candidate_1 (struct ivopts_data *dat
*** 1852,1865
{
unsigned i;
struct iv_cand *cand = NULL;
! tree type;
if (base)
{
! type = TREE_TYPE (base);
! if (!TYPE_UNSIGNED (type))
{
- type = unsigned_type_for (type);
base = fold_convert (type, base);
if (step)
step = fold_convert (type, step);
--- 1868,1881
{
unsigned i;
struct iv_cand *cand = NULL;
! tree type, orig_type;
if (base)
{
! orig_type = TREE_TYPE (base);
! type = generic_type_for (orig_type);
! if (type != orig_type)
{
base = fold_convert (type, base);
if (step)
step = fold_convert (type, step);
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From falk at debian dot org 2005-03-29 21:38 --- (In reply to comment #9) > This patch should fix the problem Yes, it does. (I haven't tried bootstrapping, though.) Thanks for fixing this so quickly! -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From tsv at solvo dot ru 2005-03-30 09:43 --- It does work for me too. Thank you for quick fix. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From rakdver at gcc dot gnu dot org 2005-04-01 20:00 --- http://gcc.gnu.org/ml/gcc-patches/2005-04/msg00097.html -- What|Removed |Added Keywords||patch http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From mmitchel at gcc dot gnu dot org 2005-04-04 23:14 --- This has been approved by RTH here: http://gcc.gnu.org/ml/gcc-patches/2005-04/msg00428.html Please apply to 4.0 and mainline. Thanks! -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From cvs-commit at gcc dot gnu dot org 2005-04-05 23:57 --- Subject: Bug 20625 CVSROOT:/cvs/gcc Module name:gcc Changes by: [EMAIL PROTECTED] 2005-04-05 23:57:02 Modified files: gcc: ChangeLog tree-ssa-loop-ivopts.c Log message: PR target/20625 * tree-ssa-loop-ivopts.c (generic_type_for): New function. (add_candidate_1): Use generic_type_for instead of unsigned_type_for. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.8156&r2=2.8157 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-loop-ivopts.c.diff?cvsroot=gcc&r1=2.57&r2=2.58 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From cvs-commit at gcc dot gnu dot org 2005-04-06 00:32 --- Subject: Bug 20625 CVSROOT:/cvs/gcc Module name:gcc Branch: gcc-4_0-branch Changes by: [EMAIL PROTECTED] 2005-04-06 00:32:37 Modified files: gcc: ChangeLog tree-ssa-loop-ivopts.c Log message: PR target/20625 * tree-ssa-loop-ivopts.c (generic_type_for): New function. (add_candidate_1): Use generic_type_for instead of unsigned_type_for. Patches: http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=2.7592.2.132&r2=2.7592.2.133 http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-loop-ivopts.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=2.49.2.2&r2=2.49.2.3 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-04-07 21:00 --- Fixed. -- What|Removed |Added Status|NEW |RESOLVED Resolution||FIXED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From tsv at solvo dot ru 2005-05-05 19:07 ---
gcc version 4.0.0 20050423 (Red Hat 4.0.0-2)
Here is another test case that generates unaligned access exception:
typedef union
{
short i16;
unsigned short u16;
int i32;
unsigned int u32;
long i64;
unsigned long u64;
double dbl;
unsigned char byt;
char *str;
} DBusBasicValue;
void foo(void *p)
{
DBusBasicValue *a;
a = p;
a->byt = 'a';
}
int main()
{
# include
# include
unsigned int buf[2] =
{
SSIN_UACPROC, UAC_SIGBUS | UAC_NOPRINT
};
char buff[100];
syscall(__NR_osf_setsysinfo, SSI_NVPAIRS, buf, 1, 0, 0, 0);
foo(&buff[1]);
}
--
What|Removed |Added
Status|RESOLVED|REOPENED
Resolution|FIXED |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-05-05 19:10 --- (In reply to comment #17) > gcc version 4.0.0 20050423 (Red Hat 4.0.0-2) > > Here is another test case that generates unaligned access exception: That code is invalid due to the alignment requirements in standard C. The orginal testcase has been fixed. -- What|Removed |Added Status|REOPENED|RESOLVED Resolution||FIXED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From tsv at solvo dot ru 2005-05-05 19:16 --- I just extracted it from "dbus" package which I am testing on linux/alpha platform. There are other packages (mozilla one of them) that started to generate unaligned access exceptions then built by gcc 4.0. Should not be some warning to be generated? Thank you. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-05-05 19:22 --- (In reply to comment #19) > Should not be some warning to be generated? There is a warning if going directly from char * to the union pointer but since you go through a void pointer, the warning is gone. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From tsv at solvo dot ru 2005-05-05 20:03 --- (In reply to comment #20) > (In reply to comment #19) > > Should not be some warning to be generated? > > There is a warning if going directly from char * to the union pointer but since you go through a void > pointer, the warning is gone. Yes, it does. DEC C generates exactly the same code for "foo" function. So, I am sorry for my wrong testcase. I am trying to find out where unaligned pointer is came from. Going couple functions back I found that it is the address if "unsigned char" variable allocated on stack. Should I look at this issue or it might be possible in theory and I should report about improper coding practice to the author of the code? Thank you for your attention -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From pinskia at physics dot uc dot edu 2005-05-05 20:06 --- Subject: Re: [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception" On May 5, 2005, at 4:03 PM, tsv at solvo dot ru wrote: > I am trying to find out where unaligned pointer is came from. Going > couple > functions back I found that it is the address if "unsigned char" > variable > allocated on stack. Should I look at this issue or it might be > possible in > theory and I should report about improper coding practice to the > author of the code? Characters have alignment of 1. I would report it back to the author of the code. -- Pinski -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From tsv at solvo dot ru 2005-05-11 20:39 --- (In reply to comment #22) > Subject: Re: [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception" > > > On May 5, 2005, at 4:03 PM, tsv at solvo dot ru wrote: > > > I am trying to find out where unaligned pointer is came from. Going > > couple > > functions back I found that it is the address if "unsigned char" > > variable > > allocated on stack. Should I look at this issue or it might be > > possible in > > theory and I should report about improper coding practice to the > > author of the code? > > Characters have alignment of 1. I would report it back to the author > of the code. > > > -- Pinski > > Sorry if it is not belong here. Just a quick question: There are still unaligned exceptions generated (even by gcc(libgcj) code itself). Should I open a new bug report or could continue attach to this one? Thank you -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
[Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
--- Additional Comments From falk at debian dot org 2005-05-17 14:07 --- (In reply to comment #23) > Sorry if it is not belong here. Just a quick question: There are still > unaligned > exceptions generated (even by gcc(libgcj) code itself). Should I open a new > bug > report or could continue attach to this one? Please open a new one, since this issue should really be fixed by Zdenek's patch. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20625
Re: [Bug target/20625] [4.0/4.1 regression] ivopts produces code that generates "unaligned access exception"
On May 5, 2005, at 4:03 PM, tsv at solvo dot ru wrote: I am trying to find out where unaligned pointer is came from. Going couple functions back I found that it is the address if "unsigned char" variable allocated on stack. Should I look at this issue or it might be possible in theory and I should report about improper coding practice to the author of the code? Characters have alignment of 1. I would report it back to the author of the code. -- Pinski
