On Wed, May 24, 2023 at 1:16 AM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> While trying to understand how to use the ! operand for match
> patterns, I noticed that the debug dumps would print out applying
> a pattern but nothing when it was rejected in the end. This was confusing
> me.
> This adds that by emitting a dump for the failed case.
> Note the patch is little more complex as we don't want to print out
> if debug counter rejected the pattern and then we need to fix up
> when we mark needing a label or not.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
Hmm, can we maybe simply move the
if (UNLIKELY
(debug_dump)) fprintf (dump_file, "Applying pattern %s:%d, %s:%d\n",
"match.pd", 1157, __FILE__, __LINE__);
right before the return true; instead?
> gcc/ChangeLog:
>
> * genmatch.cc (needs_label): New variable
> (expr::gen_transform): Set needs_label
> if we use the local_label.
> (dt_simplify::gen_1): Use `_1` for the debug count label.
> After the local label, emit debug print for the failure.
> Emit `_1` label if needed.
> ---
> gcc/genmatch.cc | 28 ++++++++++++++++++++++++----
> 1 file changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/gcc/genmatch.cc b/gcc/genmatch.cc
> index 177c13d87cb..2ea80d341a2 100644
> --- a/gcc/genmatch.cc
> +++ b/gcc/genmatch.cc
> @@ -2433,6 +2433,7 @@ capture_info::walk_c_expr (c_expr *e)
> /* The current label failing the current matched pattern during
> code generation. */
> static char *fail_label;
> +static bool needs_label;
>
> /* Code generation off the decision tree and the refered AST nodes. */
>
> @@ -2611,6 +2612,7 @@ expr::gen_transform (FILE *f, int indent, const char
> *dest, bool gimple,
> fprintf_indent (f, indent,
> "if (!_r%d) goto %s;\n",
> depth, fail_label);
> + needs_label = true;
> if (*opr == CONVERT_EXPR)
> {
> indent -= 4;
> @@ -2640,11 +2642,13 @@ expr::gen_transform (FILE *f, int indent, const char
> *dest, bool gimple,
> {
> fprintf_indent (f, indent, "if (!_r%d)\n", depth);
> fprintf_indent (f, indent, " goto %s;\n", fail_label);
> + needs_label = true;
> }
> if (force_leaf)
> {
> fprintf_indent (f, indent, "if (EXPR_P (_r%d))\n", depth);
> fprintf_indent (f, indent, " goto %s;\n", fail_label);
> + needs_label = true;
> }
> if (*opr == CONVERT_EXPR)
> {
> @@ -3409,7 +3413,8 @@ dt_simplify::gen_1 (FILE *f, int indent, bool gimple,
> operand *result)
> char local_fail_label[256];
> snprintf (local_fail_label, 256, "next_after_fail%u", ++fail_label_cnt);
> fail_label = local_fail_label;
> - bool needs_label = false;
> + needs_label = false;
> + bool needs_label_1 = false;
>
> /* Analyze captures and perform early-outs on the incoming arguments
> that cover cases we cannot handle. */
> @@ -3484,8 +3489,8 @@ dt_simplify::gen_1 (FILE *f, int indent, bool gimple,
> operand *result)
>
> if (s->kind == simplify::SIMPLIFY)
> {
> - fprintf_indent (f, indent, "if (UNLIKELY (!dbg_cnt (match))) goto
> %s;\n", fail_label);
> - needs_label = true;
> + fprintf_indent (f, indent, "if (UNLIKELY (!dbg_cnt (match))) goto
> %s_1;\n", fail_label);
> + needs_label_1 = true;
> }
>
> fprintf_indent (f, indent, "if (UNLIKELY (debug_dump)) "
> @@ -3718,7 +3723,22 @@ dt_simplify::gen_1 (FILE *f, int indent, bool gimple,
> operand *result)
> indent -= 2;
> fprintf_indent (f, indent, "}\n");
> if (needs_label)
> - fprintf (f, "%s:;\n", fail_label);
> + {
> + fprintf (f, "%s:;\n", fail_label);
> + if (s->kind == simplify::SIMPLIFY)
> + {
> + fprintf_indent (f, indent, "if (UNLIKELY (debug_dump)) "
> + "fprintf (dump_file, \"Pattern failed ");
> + fprintf (f, "%%s:%%d, %%s:%%d\\n\", ");
> + output_line_directive (f,
> + result ? result->location :
> s->match->location, true,
> + true);
> + fprintf (f, ", __FILE__, __LINE__);\n");
> + }
> + }
> + if (needs_label_1)
> + fprintf (f, "%s_1:;\n", fail_label);
> + needs_label = false;
> fail_label = NULL;
> }
>
> --
> 2.31.1
>
