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[PATCH] Fix bug in int_fits_type_p
- From: Roger Sayle <roger at eyesopen dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Olivier Hainque <hainque at adacore dot com>
- Date: Fri, 24 Dec 2004 17:08:03 -0700 (MST)
- Subject: [PATCH] Fix bug in int_fits_type_p
The following patch fixes an oversight in int_fits_type_p that was
uncovered by my testing of a patch to resolve PR 19100. Following
discussion with the Ada folks on the gcc list, I preferred Olivier's
suggestion that we add an additional test for TYPE_PRECISION, which
should also help performance.
The following patch has been tested on i686-pc-linux-gnu with a full
"make bootstrap", all default languages, and regression tested with
a top-level "make -k check" with no new failures.
Ok for mainline? Best wishes for the season...
2004-12-24 Roger Sayle <roger@eyesopen.com>
Olivier Hainque <hainque@act-europe.fr>
* tree.c (int_fits_type_p): A narrower type always fits in a
wider one, except for negative values into unsigned types.
Index: tree.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree.c,v
retrieving revision 1.458
diff -c -3 -p -r1.458 tree.c
*** tree.c 23 Dec 2004 16:21:31 -0000 1.458
--- tree.c 24 Dec 2004 21:52:15 -0000
*************** int_fits_type_p (tree c, tree type)
*** 4879,4888 ****
/* Perform some generic filtering first, which may allow making a decision
even if the bounds are not constant. First, negative integers never fit
in unsigned types, */
! if ((TYPE_UNSIGNED (type) && tree_int_cst_sgn (c) < 0)
! /* Also, unsigned integers with top bit set never fit signed types. */
! || (! TYPE_UNSIGNED (type)
! && TYPE_UNSIGNED (TREE_TYPE (c)) && tree_int_cst_msb (c)))
return 0;
/* If at least one bound of the type is a constant integer, we can check
--- 4879,4895 ----
/* Perform some generic filtering first, which may allow making a decision
even if the bounds are not constant. First, negative integers never fit
in unsigned types, */
! if (TYPE_UNSIGNED (type) && tree_int_cst_sgn (c) < 0)
! return 0;
!
! /* Second, narrower types always fit in wider ones. */
! if (TYPE_PRECISION (type) > TYPE_PRECISION (TREE_TYPE (c)))
! return 1;
!
! /* Third, unsigned integers with top bit set never fit signed types. */
! if (! TYPE_UNSIGNED (type)
! && TYPE_UNSIGNED (TREE_TYPE (c))
! && tree_int_cst_msb (c))
return 0;
/* If at least one bound of the type is a constant integer, we can check
Roger
--
Roger Sayle, E-mail: roger@eyesopen.com
OpenEye Scientific Software, WWW: http://www.eyesopen.com/
Suite 1107, 3600 Cerrillos Road, Tel: (+1) 505-473-7385
Santa Fe, New Mexico, 87507. Fax: (+1) 505-473-0833