This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [patch 4/4 v4] Allow loop prefetch code to speculatively prefetch non constant steps
Am Donnerstag 20 Mai 2010 00:25:48 schrieb H.J. Lu:
> This caused:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203
H.J.,
Can you verify the following patch?
2010-05-20 Christian Borntraeger <borntraeger@de.ibm.com>
PR 44203
* gcc/tree-ssa-loop-prefetch.c: Fix logic for step calculation to
match the original (and intended) behaviour before r159557. This
changeset changed a=a+b*c to a=(a+b)*b which was obviously wrong
in two ways.
Index: gcc/tree-ssa-loop-prefetch.c
===================================================================
*** gcc/tree-ssa-loop-prefetch.c.orig
--- gcc/tree-ssa-loop-prefetch.c
*************** idx_analyze_ref (tree base, tree *index,
*** 425,449 ****
ibase = build_int_cst (TREE_TYPE (ibase), 0);
}
- if (*ar_data->step == NULL_TREE)
- *ar_data->step = step;
- else
- *ar_data->step = fold_build2 (PLUS_EXPR, sizetype,
- fold_convert (sizetype, *ar_data->step),
- fold_convert (sizetype, step));
if (TREE_CODE (base) == ARRAY_REF)
{
stepsize = array_ref_element_size (base);
if (!cst_and_fits_in_hwi (stepsize))
return false;
imult = int_cst_value (stepsize);
!
! *ar_data->step = fold_build2 (MULT_EXPR, sizetype,
! fold_convert (sizetype, *ar_data->step),
! fold_convert (sizetype, step));
idelta *= imult;
}
*ar_data->delta += idelta;
*index = ibase;
--- 425,448 ----
ibase = build_int_cst (TREE_TYPE (ibase), 0);
}
if (TREE_CODE (base) == ARRAY_REF)
{
stepsize = array_ref_element_size (base);
if (!cst_and_fits_in_hwi (stepsize))
return false;
imult = int_cst_value (stepsize);
! step = fold_build2 (MULT_EXPR, sizetype,
! fold_convert (sizetype, step),
! fold_convert (sizetype, stepsize));
idelta *= imult;
}
+ if (*ar_data->step == NULL_TREE)
+ *ar_data->step = step;
+ else
+ *ar_data->step = fold_build2 (PLUS_EXPR, sizetype,
+ fold_convert (sizetype, *ar_data->step),
+ fold_convert (sizetype, step));
*ar_data->delta += idelta;
*index = ibase;