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Re: [PATCH] Fix middle-end/81737


On Mon, Aug 14, 2017 at 10:22:09AM +0200, Richard Biener wrote:
> On Tue, Aug 8, 2017 at 7:23 PM, Marek Polacek <polacek@redhat.com> wrote:
> > On Mon, Aug 07, 2017 at 04:07:49PM +0200, Richard Biener wrote:
> >> On August 7, 2017 11:09:59 AM GMT+02:00, Marek Polacek <polacek@redhat.com> wrote:
> >> >On Mon, Aug 07, 2017 at 10:58:09AM +0200, Jakub Jelinek wrote:
> >> >> On Mon, Aug 07, 2017 at 10:47:51AM +0200, Marek Polacek wrote:
> >> >> > In my recent change I failed to check whether the type domain
> >> >> > of a type is non-NULL and this goof causes crashing on this
> >> >> > testcase.
> >> >> >
> >> >> > Bootstrapped/regtested on x86_64-linux, ok for trunk?
> >> >> >
> >> >> > 2017-08-07  Marek Polacek  <polacek@redhat.com>
> >> >> >
> >> >> >  PR middle-end/81737
> >> >> >  * fold-const.c (fold_indirect_ref_1): Check type_domain.
> >> >> >
> >> >> >  * gcc.dg/pr81737.c: New test.
> >> >>
> >> >> The old code was assuming size_zero_node if type_domain is NULL
> >> >> or TYPE_MIN_VALUE is NULL, which is reasonable for C/C++, but indeed
> >> >might
> >> >> be wrong perhaps for Fortran or Ada.
> >>
> >> It's how the middle-end defines it, so please restore this behavior (sorry for missing this in the review).  IIRC there are at least one other 'copy' of the folding somewhere.
> >
> > Sure, this patch should do it:
> >
> > Bootstrapped/regtested on x86_64-linux, ok for trunk?
> >
> > 2017-08-08  Marek Polacek  <polacek@redhat.com>
> >
> >         PR middle/81695
> >         * fold-const.c (fold_indirect_ref_1): Restore original behavior
> >         regarding size_zero_node.
> >
> > diff --git gcc/fold-const.c gcc/fold-const.c
> > index 5a118ca50a1..2c47d1d16a4 100644
> > --- gcc/fold-const.c
> > +++ gcc/fold-const.c
> > @@ -14109,22 +14109,21 @@ fold_indirect_ref_1 (location_t loc, tree type, tree op0)
> >                    && type == TREE_TYPE (op00type))
> >             {
> >               tree type_domain = TYPE_DOMAIN (op00type);
> > -             tree min;
> > +             tree min = size_zero_node;
> >               if (type_domain != NULL_TREE
> > -                 && (min = TYPE_MIN_VALUE (type_domain))
> > +                 && TYPE_MIN_VALUE (type_domain)
> >                   && TREE_CODE (min) == INTEGER_CST)
> > +               min = TYPE_MIN_VALUE (type_domain);
> 
> I think this is wrong for non-INTEGER_CST TYPE_MIN_VALUE.

Ah, right, another try:

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2017-08-16  Marek Polacek  <polacek@redhat.com>

	PR middle/81695
	* fold-const.c (fold_indirect_ref_1): Restore original behavior
	regarding size_zero_node.

diff --git gcc/fold-const.c gcc/fold-const.c
index 5a118ca50a1..0a05da0b49f 100644
--- gcc/fold-const.c
+++ gcc/fold-const.c
@@ -14109,22 +14109,19 @@ fold_indirect_ref_1 (location_t loc, tree type, tree op0)
 		   && type == TREE_TYPE (op00type))
 	    {
 	      tree type_domain = TYPE_DOMAIN (op00type);
-	      tree min;
-	      if (type_domain != NULL_TREE
-		  && (min = TYPE_MIN_VALUE (type_domain))
-		  && TREE_CODE (min) == INTEGER_CST)
+	      tree min = size_zero_node;
+	      if (type_domain && TYPE_MIN_VALUE (type_domain))
+		min = TYPE_MIN_VALUE (type_domain);
+	      offset_int off = wi::to_offset (op01);
+	      offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type));
+	      offset_int remainder;
+	      off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder);
+	      if (remainder == 0)
 		{
-		  offset_int off = wi::to_offset (op01);
-		  offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type));
-		  offset_int remainder;
-		  off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder);
-		  if (remainder == 0)
-		    {
-		      off = off + wi::to_offset (min);
-		      op01 = wide_int_to_tree (sizetype, off);
-		      return build4_loc (loc, ARRAY_REF, type, op00, op01,
-					 NULL_TREE, NULL_TREE);
-		    }
+		  off = off + wi::to_offset (min);
+		  op01 = wide_int_to_tree (sizetype, off);
+		  return build4_loc (loc, ARRAY_REF, type, op00, op01,
+				     NULL_TREE, NULL_TREE);
 		}
 	    }
 	}

	Marek


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