Standardize on VIRT_ADDR_VARIES behavior.

Otherwise, valgrind does not work on some platforms.
Problem reported by Andreas Schwab in
<http://lists.gnu.org/archive/html/emacs-devel/2011-11/msg00081.html>.
* puresize.h (pure, PURE_P): Always behave as if VIRT_ADDR_VARIES
is set, removing the need for VIRT_ADDRESS_VARIES.
(PURE_P): Use a more-efficient implementation that needs just one
comparison, not two: on x86-64 with GCC 4.6.2, this cut down the
number of instructions from 6 (xorl, cmpq, jge, xorl, cmpq, setge)
to 4 (xorl, subq, cmpq, setbe).
* alloc.c (pure): Always extern now, since that's the
VIRT_ADDR_VARIES behavior.
(PURE_POINTER_P): Use a single comparison, not two, for
consistency with the new puresize.h.
* lisp.h (PNTR_COMPARISON_TYPE): Remove; no longer needed.
* m/ibms390.h, m/intel386.h, m/template.h, s/cygwin.h, s/hpux10-20.h:
Remove VIRT_ADDR_VARIES no longer needed.

Fixes: debbugs:10042

1 files changed, 20 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 2973ecc4b57..7accd0d5eea 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,23 @@
+2011-11-20  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Standardize on VIRT_ADDR_VARIES behavior (Bug#10042).
+        Otherwise, valgrind does not work on some platforms.
+        Problem reported by Andreas Schwab in
+        <http://lists.gnu.org/archive/html/emacs-devel/2011-11/msg00081.html>.
+        * puresize.h (pure, PURE_P): Always behave as if VIRT_ADDR_VARIES
+        is set, removing the need for VIRT_ADDRESS_VARIES.
+        (PURE_P): Use a more-efficient implementation that needs just one
+        comparison, not two: on x86-64 with GCC 4.6.2, this cut down the
+        number of instructions from 6 (xorl, cmpq, jge, xorl, cmpq, setge)
+        to 4 (xorl, subq, cmpq, setbe).
+        * alloc.c (pure): Always extern now, since that's the
+        VIRT_ADDR_VARIES behavior.
+        (PURE_POINTER_P): Use a single comparison, not two, for
+        consistency with the new puresize.h.
+        * lisp.h (PNTR_COMPARISON_TYPE): Remove; no longer needed.
+        * m/ibms390.h, m/intel386.h, m/template.h, s/cygwin.h, s/hpux10-20.h:
+        Remove VIRT_ADDR_VARIES no longer needed.
+
 2011-11-19  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (x_write_glyphs, draw_phys_cursor_glyph)