[Bug target/29967] wrong code generated with -O2 on sh4-linux

[pinskia at gmail dot com]

--- Comment #3 from pinskia at gmail dot com  2006-11-24 06:32 ---
Subject: Re:  wrong code generated with -O2 on sh4-linux

On Fri, 2006-11-24 at 06:20 +, sugioka at itonet dot co dot jp
wrote:
> 
> --- Comment #2 from sugioka at itonet dot co dot jp  2006-11-24 06:20 
> ---
> This code is reduced from gcc/java/expr.c(add_type_assertion).
> jc1 is really miscompiled on sh4-linux, so bootstrapping
> libgcj fails with segmentation fault in jc1.
> 
> Should gcc/java/expr.c be fixed ?

Yes it should.

A warning is hard here unless we change the warning to be based on the
flow. 

Thanks,
Andrew Pinski


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29967

Re: [Bug target/29967] wrong code generated with -O2 on sh4-linux

[Andrew Pinski]

On Fri, 2006-11-24 at 06:20 +, sugioka at itonet dot co dot jp
wrote:
> 
> --- Comment #2 from sugioka at itonet dot co dot jp  2006-11-24 06:20 
> ---
> This code is reduced from gcc/java/expr.c(add_type_assertion).
> jc1 is really miscompiled on sh4-linux, so bootstrapping
> libgcj fails with segmentation fault in jc1.
> 
> Should gcc/java/expr.c be fixed ?

Yes it should.

A warning is hard here unless we change the warning to be based on the
flow. 

Thanks,
Andrew Pinski

[Bug target/29967] wrong code generated with -O2 on sh4-linux

[sugioka at itonet dot co dot jp]

--- Comment #2 from sugioka at itonet dot co dot jp  2006-11-24 06:20 
---
This code is reduced from gcc/java/expr.c(add_type_assertion).
jc1 is really miscompiled on sh4-linux, so bootstrapping
libgcj fails with segmentation fault in jc1.

Should gcc/java/expr.c be fixed ?

It would be better if I got warning about aliasing rule violation.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29967

[Bug target/29967] wrong code generated with -O2 on sh4-linux

[pinskia at gcc dot gnu dot org]

--- Comment #1 from pinskia at gcc dot gnu dot org  2006-11-24 06:00 ---
  *pp = malloc (sizeof (int));
  **(int **)pp = code;  /* segmentation fault here */

You are violating aliasing rules in that "void*" does not alias "int*" so the
optimizers are swapping around the store to *pp and the load of *(int**)(pp).


-- 

pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution||INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29967