On Mon, Apr 30, 2012 at 3:39 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> compute_all_dependences in 4.7+ can fail, and cond_if_else_store_replacement
> isn't prepared to handle the chrec_dont_know DDR added there in case of
> failure (with NULL DDR_A/DDR_B).
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
> ok for trunk/4.7?
Ok.
> BTW, tree-ssa-loop-prefetch.c seems to have the same problem, but no idea
> how that should be handled in there...
I think it handles it fine by treating the chrec_dont_know DDR
properly? I suppose
failing would be an option, too, by returning a bool from
determine_loop_nest_reuse
and adjusting its single caller.
Thanks,
Richard.
> 2012-04-30 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/53163
> * tree-ssa-phiopt.c (cond_if_else_store_replacement): Don't ignore
> return value from compute_all_dependences.
>
> * gcc.c-torture/compile/pr53163.c: New test.
>
> --- gcc/tree-ssa-phiopt.c.jj 2012-04-30 08:06:18.000000000 +0200
> +++ gcc/tree-ssa-phiopt.c 2012-04-30 08:59:16.726488101 +0200
> @@ -1624,8 +1624,17 @@ cond_if_else_store_replacement (basic_bl
> /* Compute and check data dependencies in both basic blocks. */
> then_ddrs = VEC_alloc (ddr_p, heap, 1);
> else_ddrs = VEC_alloc (ddr_p, heap, 1);
> - compute_all_dependences (then_datarefs, &then_ddrs, NULL, false);
> - compute_all_dependences (else_datarefs, &else_ddrs, NULL, false);
> + if (!compute_all_dependences (then_datarefs, &then_ddrs, NULL, false)
> + || !compute_all_dependences (else_datarefs, &else_ddrs, NULL, false))
> + {
> + free_dependence_relations (then_ddrs);
> + free_dependence_relations (else_ddrs);
> + free_data_refs (then_datarefs);
> + free_data_refs (else_datarefs);
> + VEC_free (gimple, heap, then_stores);
> + VEC_free (gimple, heap, else_stores);
> + return false;
> + }
> blocks[0] = then_bb;
> blocks[1] = else_bb;
> blocks[2] = join_bb;
> --- gcc/testsuite/gcc.c-torture/compile/pr53163.c.jj 2012-04-30
> 09:21:40.950512562 +0200
> +++ gcc/testsuite/gcc.c-torture/compile/pr53163.c 2012-04-30
> 09:21:20.000000000 +0200
> @@ -0,0 +1,34 @@
> +/* PR tree-optimization/53163 */
> +
> +struct S { int s; } b, f;
> +int a, c;
> +
> +void
> +foo (void)
> +{
> + int d, e;
> + for (d = 4; d < 19; ++d)
> + for (e = 2; e >= 0; e--)
> + {
> + a = 0;
> + a = 1;
> + }
> +}
> +
> +void
> +bar (void)
> +{
> + int g, h, i;
> + for (i = 1; i >= 0; i--)
> + {
> + b = f;
> + for (g = 0; g <= 1; g++)
> + {
> + if (c)
> + break;
> + for (h = 0; h <= 1; h++)
> + foo ();
> + foo ();
> + }
> + }
> +}
>
> Jakub
