On Mon, 18 Feb 2013, Jakub Jelinek wrote:
> Hi!
>
> On the following testcase, a = a / 8; looks like reasonable reduction
> statement, but we pattern recognize it as
> patt_1 = a < 0 ? 7 : 0;
> patt_2 = a + patt_1;
> a = patt2 >> 3;
> and in the first pattern stmt the reduction operand is in the condition of
> COND_EXPR, not operands as vectorizable_reduction was asserting. Generally,
> it couldn't be used anywhere in a pattern stmt, it could be just some
> preparation statement.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
Ok.
Thanks,
Richard.
> 2013-02-18 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/56350
> * tree-vect-loop.c (vectorizable_reduction): If orig_stmt, return false
> if haven't found reduction or nested cycle operand, rather than
> asserting we must find it.
>
> * gcc.dg/pr56350.c: New test.
>
> --- gcc/tree-vect-loop.c.jj 2013-01-15 10:30:19.000000000 +0100
> +++ gcc/tree-vect-loop.c 2013-02-18 11:32:30.306566358 +0100
> @@ -4692,7 +4692,7 @@ vectorizable_reduction (gimple stmt, gim
> The last use is the reduction variable. In case of nested cycle this
> assumption is not true: we use reduc_index to record the index of the
> reduction variable. */
> - for (i = 0; i < op_type-1; i++)
> + for (i = 0; i < op_type - 1; i++)
> {
> /* The condition of COND_EXPR is checked in vectorizable_condition().
> */
> if (i == 0 && code == COND_EXPR)
> @@ -4724,11 +4724,18 @@ vectorizable_reduction (gimple stmt, gim
> if (!vectype_in)
> vectype_in = tem;
> gcc_assert (is_simple_use);
> - gcc_assert (dt == vect_reduction_def
> - || dt == vect_nested_cycle
> - || ((dt == vect_internal_def || dt == vect_external_def
> - || dt == vect_constant_def || dt == vect_induction_def)
> - && nested_cycle && found_nested_cycle_def));
> + if (!(dt == vect_reduction_def
> + || dt == vect_nested_cycle
> + || ((dt == vect_internal_def || dt == vect_external_def
> + || dt == vect_constant_def || dt == vect_induction_def)
> + && nested_cycle && found_nested_cycle_def)))
> + {
> + /* For pattern recognized stmts, orig_stmt might be a reduction,
> + but some helper statements for the pattern might not, or
> + might be COND_EXPRs with reduction uses in the condition. */
> + gcc_assert (orig_stmt);
> + return false;
> + }
> if (!found_nested_cycle_def)
> reduc_def_stmt = def_stmt;
>
> --- gcc/testsuite/gcc.dg/pr56350.c.jj 2013-02-18 11:30:12.117327599 +0100
> +++ gcc/testsuite/gcc.dg/pr56350.c 2013-02-18 11:29:59.000000000 +0100
> @@ -0,0 +1,13 @@
> +/* PR tree-optimization/56350 */
> +/* { dg-do compile } */
> +/* { dg-options "-O -ftree-vectorize" } */
> +
> +int a, b, c;
> +
> +void
> +f (void)
> +{
> + for (; c; c++)
> + for (b = 0; b < 2; b++)
> + a /= 8;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend
