Re: [PATCH, IPA-SRA] Fix PR 45644

[Richard Guenther <rguenther at suse dot de>]

On Wed, 15 Sep 2010, Martin Jambor wrote:

> Hi,
> 
> IPA-SRA was never meant to handle bit-fields (because of even more
> unclear cost considerations) and so I did not bother to make the
> call statement modification work with them and with the new MEM_REF
> implementation it doesn't.  However, the detection condition is
> wrong and fails to catch some cases.  Becase it is at a place where
> BIT_FIELD_REFs do not get, I changed it to look at the field
> declaration directly, just as we do in build_ref_for_model.
> 
> This fixes 450.soplex (at least the test run, I'm running a reference
> run now) and I have bootstrapped and tested it without any issues on
> x86_64-linux.  OK for trunk?

Ok.

Thanks,
Richard.

> Thanks,
> 
> Martin
> 
> 
> 2010-09-14  Martin Jambor  <mjambor@suse.cz>
> 
> 	PR middle-end/45644
> 	* tree-sra.c (create_access): Check for bit-fields directly.
> 
> 	* testsuite/gcc.dg/ipa/pr45644.c: New test.
> 
> Index: mine/gcc/tree-sra.c
> ===================================================================
> --- mine.orig/gcc/tree-sra.c
> +++ mine/gcc/tree-sra.c
> @@ -774,12 +774,13 @@ create_access (tree expr, gimple stmt, b
>  	  disqualify_candidate (base, "Encountered a variable sized access.");
>  	  return NULL;
>  	}
> -      if ((offset % BITS_PER_UNIT) != 0 || (size % BITS_PER_UNIT) != 0)
> +      if (TREE_CODE (expr) == COMPONENT_REF
> +	  && DECL_BIT_FIELD (TREE_OPERAND (expr, 1)))
>  	{
> -	  disqualify_candidate (base,
> -				"Encountered an acces not aligned to a byte.");
> +	  disqualify_candidate (base, "Encountered a bit-field access.");
>  	  return NULL;
>  	}
> +      gcc_checking_assert ((offset % BITS_PER_UNIT) == 0);
>  
>        if (ptr)
>  	mark_parm_dereference (base, offset + size, stmt);
> Index: mine/gcc/testsuite/gcc.dg/ipa/pr45644.c
> ===================================================================
> --- /dev/null
> +++ mine/gcc/testsuite/gcc.dg/ipa/pr45644.c
> @@ -0,0 +1,35 @@
> +/* Verify that we do not IPA-SRA bitfields.  */
> +/* { dg-do run } */
> +/* { dg-options "-O2"  } */
> +
> +extern void abort (void);
> +
> +struct S
> +{
> +  int j : 8;
> +  int i : 24;
> +  int l;
> +};
> +
> +static int __attribute__((noinline)) foo (struct S *s)
> +{
> +  int z = s->i;
> +  if (z != 777)
> +    abort ();
> +  return 0;
> +}
> +
> +int __attribute__((noinline)) bar (struct S *s)
> +{
> +  return foo (s);
> +}
> +
> +int main (int argc, char *argv[])
> +{
> +  struct S s;
> +  s.j = 5;
> +  s.i = 777;
> +  s.l = -1; 
> +
> +  return bar (&s);
> +}
> 
> 

-- 
Richard Guenther <rguenther@suse.de>
Novell / SUSE Labs
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