Re: [PATCH, PR 42006] Dont mark replacement variables for renaming

[Richard Guenther <rguenther at suse dot de>]

On Fri, 27 Nov 2009, Martin Jambor wrote:

> Hi,
> 
> in PR 42006, IPA-SRA removes an unused scalar parameter because the
> value passed to it is not used.  However, the parameter is used to
> drive a loop and so it needs to be replaced by a variable.  IPA-SRA
> currently creates that variable with make_rename_temp which marks it
> for renaming but then proceeds with creating SSA_NAMEs on its own,
> replacing one for one.  For some reason, the (unnecessary) renaming
> then messes this up.  I even believe this might be a known "problem."
> 
> If I just use create_tmp_var (and then mark vectors and complex
> numbers as gimple registers) the problem goes away and it is probably
> the right thing to do anyway, so this is what the patch below does.

Um, yeah.  You can't just arbitrarily rename things.

> Bootstrapped and tested on x86_64-linux. OK for trunk?

Ok.

Thanks,
Richard.

> Thanks,
> 
> Martin
> 
> 
> 2009-11-27  Martin Jambor  <mjambor@suse.cz>
> 
> 	PR middle-end/42006
> 	* tree-sra.c (get_replaced_param_substitute): Call create_tmp_var
> 	instead of create_tmp_var.  Set DECL_GIMPLE_REG_P to one manually
> 	for vector and complex types.
> 	(get_adjustment_for_base): Describe return value in the comment.
> 
> 	* testsuite/gcc.c-torture/execute/pr42006.c: New test.
> 
> Index: mine/gcc/tree-sra.c
> ===================================================================
> --- mine.orig/gcc/tree-sra.c
> +++ mine/gcc/tree-sra.c
> @@ -3478,7 +3478,10 @@ get_replaced_param_substitute (struct ip
>      {
>        char *pretty_name = make_fancy_name (adj->base);
>  
> -      repl = make_rename_temp (TREE_TYPE (adj->base), "ISR");
> +      repl = create_tmp_var (TREE_TYPE (adj->base), "ISR");
> +      if (TREE_CODE (TREE_TYPE (repl)) == COMPLEX_TYPE
> +	  || TREE_CODE (TREE_TYPE (repl)) == VECTOR_TYPE)
> +	DECL_GIMPLE_REG_P (repl) = 1;
>        DECL_NAME (repl) = get_identifier (pretty_name);
>        obstack_free (&name_obstack, pretty_name);
>  
> @@ -3516,7 +3519,8 @@ get_adjustment_for_base (ipa_parm_adjust
>  /* Callback for scan_function.  If the statement STMT defines an SSA_NAME of a
>     parameter which is to be removed because its value is not used, replace the
>     SSA_NAME with a one relating to a created VAR_DECL and replace all of its
> -   uses too.  DATA is a pointer to an adjustments vector.  */
> +   uses too and return true (update_stmt is then issued for the statement by
> +   the caller).  DATA is a pointer to an adjustments vector.  */
>  
>  static bool
>  replace_removed_params_ssa_names (gimple stmt, void *data)
> Index: mine/gcc/testsuite/gcc.c-torture/execute/pr42006.c
> ===================================================================
> --- /dev/null
> +++ mine/gcc/testsuite/gcc.c-torture/execute/pr42006.c
> @@ -0,0 +1,33 @@
> +extern void abort (void);
> +
> +static unsigned int
> +my_add(unsigned int si1, unsigned int si2)
> +{
> +  return (si1 > (50-si2)) ? si1 : (si1 + si2);
> +}
> +
> +static unsigned int
> +my_shift(unsigned int left, unsigned int right)
> +{
> +  return  (right > 100) ? left : (left >> right);
> +}
> +
> +static int func_4(unsigned int p_6)
> +{
> +  int count = 0;
> +  for (p_6 = 1; p_6 < 3; p_6 = my_add(p_6, 1))
> +    {
> +      if (count++ > 1)
> +	abort ();
> +
> +      if (my_shift(p_6, p_6))
> +	return 0;
> +    }
> +  return 0;
> +}
> +
> +int main(void)
> +{
> +  func_4(0);
> +  return 0;
> +}
> 
> 

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