On Tue, Sep 13, 2016 at 9:46 AM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> The following testcase ICEs because SSA_NAME IMM links are broken.
> I've tracked it to DOM's optimize_stmt, a GIMPLE_COND in there is
> changed, marked as modified, then in optimize_stmt
> if (gimple_modified_p (stmt) || modified_p)
> {
> tree val = NULL;
>
> update_stmt_if_modified (stmt);
> and a few lines later changed again:
> if (gimple_code (stmt) == GIMPLE_COND)
> {
> if (integer_zerop (val))
> gimple_cond_make_false (as_a <gcond *> (stmt));
> else if (integer_onep (val))
> gimple_cond_make_true (as_a <gcond *> (stmt));
> without update_stmt. As this is a function which update_stmt_if_modified
> a few lines before, I think it is fine to update_stmt it immediately.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok if it doesn't do the update twice this way (we do it the "fancy way" to
only update stmts we modified and do it only once).
Richard.
> 2016-09-13 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/77454
> * tree-ssa-dom.c (optimize_stmt): Call update_stmt after changing
> GIMPLE_COND. Formatting fix.
>
> * gcc.dg/pr77454.c: New test.
>
> --- gcc/tree-ssa-dom.c.jj 2016-07-22 15:55:30.000000000 +0200
> +++ gcc/tree-ssa-dom.c 2016-09-09 12:29:28.006188533 +0200
> @@ -1927,8 +1927,9 @@ optimize_stmt (basic_block bb, gimple_st
>
> if (gimple_code (stmt) == GIMPLE_COND)
> val = fold_binary_loc (gimple_location (stmt),
> - gimple_cond_code (stmt), boolean_type_node,
> - gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));
> + gimple_cond_code (stmt), boolean_type_node,
> + gimple_cond_lhs (stmt),
> + gimple_cond_rhs (stmt));
> else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
> val = gimple_switch_index (swtch_stmt);
>
> @@ -1946,6 +1947,8 @@ optimize_stmt (basic_block bb, gimple_st
> gimple_cond_make_true (as_a <gcond *> (stmt));
> else
> gcc_unreachable ();
> +
> + update_stmt (stmt);
> }
>
> /* Further simplifications may be possible. */
> --- gcc/testsuite/gcc.dg/pr77454.c.jj 2016-09-09 12:34:47.540537483 +0200
> +++ gcc/testsuite/gcc.dg/pr77454.c 2016-09-09 12:32:47.000000000 +0200
> @@ -0,0 +1,28 @@
> +/* PR tree-optimization/77454 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +void
> +foo (unsigned char x, char y)
> +{
> + while (x != 0)
> + {
> + unsigned char *a = &x;
> + int b;
> +
> + if (y != 0)
> + a = (unsigned char *) &y;
> + else if (y + 1 != 0)
> + a = (unsigned char *) &y;
> + for (x = 0; x < 1; ++x)
> + b = 0;
> + for (y = 0; y < 3; ++y)
> + {
> + y = !!y;
> + if (y != 0)
> + x = y;
> + }
> + if ((b != 0 ? -1 : *a) < (y = b))
> + b = 1;
> + }
> +}
>
> Jakub
