On Mon, 15 Apr 2013, Jakub Jelinek wrote:
> Hi!
>
> record_increment failed to verify that initializer is usable, which it is
> only if cand_stmt is an addition (CAND_ADD can be e.g. even on a cast of
> addition to some type of the same precision etc.) and one of the operands is
> c->base_expr (because then the other operand necessarily has to be the rest,
> but the code was only checking one of the operands, but cand_stmt e.g. can
> be a sum of two SSA_NAMEs where each of those adds some multiply of one of
> base_expr operands and some multiply of the c->stride. If we set
> initializer to randomly chosen operand of such stmt, while we'll have the
> right multiply of c->stride, the base_expr might be wrong.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk/4.8?
Ok.
Thanks,
Richard.
> 2013-04-15 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/56962
> * gimple-ssa-strength-reduction.c (record_increment): Only set
> initializer if gimple_assign_rhs_code is {,POINTER_}PLUS_EXPR and
> either rhs1 or rhs2 is equal to c->base_expr.
>
> * gcc.c-torture/execute/pr56962.c: New test.
>
> --- gcc/gimple-ssa-strength-reduction.c.jj 2013-01-11 09:02:50.000000000
> +0100
> +++ gcc/gimple-ssa-strength-reduction.c 2013-04-15 11:59:46.668463873
> +0200
> @@ -1829,16 +1829,20 @@ record_increment (slsr_cand_t c, double_
> if (c->kind == CAND_ADD
> && c->index == increment
> && (increment.sgt (double_int_one)
> - || increment.slt (double_int_minus_one)))
> + || increment.slt (double_int_minus_one))
> + && (gimple_assign_rhs_code (c->cand_stmt) == PLUS_EXPR
> + || gimple_assign_rhs_code (c->cand_stmt) == POINTER_PLUS_EXPR))
> {
> - tree t0;
> + tree t0 = NULL_TREE;
> tree rhs1 = gimple_assign_rhs1 (c->cand_stmt);
> tree rhs2 = gimple_assign_rhs2 (c->cand_stmt);
> if (operand_equal_p (rhs1, c->base_expr, 0))
> t0 = rhs2;
> - else
> + else if (operand_equal_p (rhs2, c->base_expr, 0))
> t0 = rhs1;
> - if (SSA_NAME_DEF_STMT (t0) && gimple_bb (SSA_NAME_DEF_STMT (t0)))
> + if (t0
> + && SSA_NAME_DEF_STMT (t0)
> + && gimple_bb (SSA_NAME_DEF_STMT (t0)))
> {
> incr_vec[incr_vec_len].initializer = t0;
> incr_vec[incr_vec_len++].init_bb
> --- gcc/testsuite/gcc.c-torture/execute/pr56962.c.jj 2013-04-15
> 12:09:24.781355085 +0200
> +++ gcc/testsuite/gcc.c-torture/execute/pr56962.c 2013-04-15
> 12:09:19.985381802 +0200
> @@ -0,0 +1,30 @@
> +/* PR tree-optimization/56962 */
> +
> +extern void abort (void);
> +long long v[144];
> +
> +__attribute__((noinline, noclone)) void
> +bar (long long *x)
> +{
> + if (x != &v[29])
> + abort ();
> +}
> +
> +__attribute__((noinline, noclone)) void
> +foo (long long *x, long y, long z)
> +{
> + long long a, b, c;
> + a = x[z * 4 + y * 3];
> + b = x[z * 5 + y * 3];
> + c = x[z * 5 + y * 4];
> + x[y * 4] = a;
> + bar (&x[z * 5 + y]);
> + x[z * 5 + y * 5] = b + c;
> +}
> +
> +int
> +main ()
> +{
> + foo (v, 24, 1);
> + return 0;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
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