[PATCH] Amend match.pd syntax with force-simplified results

[Richard Biener]

On Fri, 31 Jul 2020, Marc Glisse wrote:

> On Fri, 31 Jul 2020, Richard Biener wrote:
> 
> > Or we simply automatically disable those patterns for GENERIC
> > (though that would probably be unexpected).
> 
> Since the definition is not clear, whatever we do will be unexpected at least
> in some cases. Disabling it for GENERIC for now seems ok to me, we can always
> extend it later...

Fair enough.  I'm going to test and install the following which means
! using patterns need to be guarded with #if GIMPLE for now.

Richard.

>From 3237456abe8d384ada9ef6b972ee0bd81caf8112 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Mon, 3 Aug 2020 10:30:49 +0200
Subject: [PATCH] mark match.pd ! not implemented on GENERIC

This makes us error when the ! operator modifier is encountered
when not targeting GIMPLE.

2020-08-03  Richard Biener  <rguenther@suse.de>

	* genmatch.c (parser::gimple): New.
	(parser::parser): Initialize gimple flag member.
	(parser::parse_expr): Error on ! operator modifier when
	not targeting GIMPLE.
	(main): Pass down gimple flag to parser ctor.

	* doc/match-and-simplify.texi: Amend accordingly.
---
 gcc/doc/match-and-simplify.texi |  3 ++-
 gcc/genmatch.c                  | 11 ++++++++---
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/gcc/doc/match-and-simplify.texi b/gcc/doc/match-and-simplify.texi
index 41980acbfe9..8752bd2afe1 100644
--- a/gcc/doc/match-and-simplify.texi
+++ b/gcc/doc/match-and-simplify.texi
@@ -374,7 +374,8 @@ for example
 
 which moves the outer @code{plus} operation to the inner arms
 of the @code{vec_cond} expression but only if the actual plus
-operations both simplify.
+operations both simplify.  Note this is currently only supported
+for code generation targeting @code{GIMPLE}.
 
 As intermediate conversions are often optional there is a way to
 avoid the need to repeat patterns both with and without such
diff --git a/gcc/genmatch.c b/gcc/genmatch.c
index 88459d9686e..109dce2d469 100644
--- a/gcc/genmatch.c
+++ b/gcc/genmatch.c
@@ -3946,7 +3946,7 @@ write_header (FILE *f, const char *head)
 class parser
 {
 public:
-  parser (cpp_reader *);
+  parser (cpp_reader *, bool gimple);
 
 private:
   const cpp_token *next ();
@@ -3983,6 +3983,7 @@ private:
   void finish_match_operand (operand *);
 
   cpp_reader *r;
+  bool gimple;
   vec<c_expr *> active_ifs;
   vec<vec<user_id *> > active_fors;
   hash_set<user_id *> *oper_lists_set;
@@ -4249,6 +4250,9 @@ parser::parse_expr ()
       && token->type == CPP_NOT
       && !(token->flags & PREV_WHITE))
     {
+      if (!gimple)
+	fatal_at (token, "forcing simplification to a leaf is not supported "
+		  "for GENERIC");
       eat_token (CPP_NOT);
       e->force_leaf = true;
     }
@@ -5042,9 +5046,10 @@ parser::finish_match_operand (operand *op)
 
 /* Main entry of the parser.  Repeatedly parse outer control structures.  */
 
-parser::parser (cpp_reader *r_)
+parser::parser (cpp_reader *r_, bool gimple_)
 {
   r = r_;
+  gimple = gimple_;
   active_ifs = vNULL;
   active_fors = vNULL;
   simplifiers = vNULL;
@@ -5151,7 +5156,7 @@ main (int argc, char **argv)
 #include "internal-fn.def"
 
   /* Parse ahead!  */
-  parser p (r);
+  parser p (r, gimple);
 
   if (gimple)
     write_header (stdout, "gimple-match-head.c");
-- 
2.26.2