+++ /dev/null
-From a6219e8e0719b14f474b0dcaa7bde2f4e57474f9 Mon Sep 17 00:00:00 2001
-From: Jakub Jelinek <jakub@redhat.com>
-Date: Wed, 17 Nov 2021 13:45:53 +0100
-Subject: [PATCH] ranger: Fix up fold_using_range::range_of_address [PR103255]
-
-If on &base->member the offset isn't constant or isn't zero and
--fdelete-null-pointer-checks and not -fwrapv-pointer and base has a range
-that doesn't include NULL, we return the range of the base.
-Usually it isn't a big deal, because for most pointers we just use
-varying, range_zero and range_nonzero ranges and nothing beyond that,
-but if a pointer is initialized from a constant, we actually track the
-exact range and in that case this causes miscompilation.
-As discussed on IRC, I think doing something like:
- offset_int off2;
- if (off_cst && off.is_constant (&off2))
- {
- tree cst = wide_int_to_tree (sizetype, off2 / BITS_PER_UNIT);
- // adjust range r with POINTER_PLUS_EXPR cst
- if (!range_includes_zero_p (&r))
- return true;
- }
- // Fallback
- r = range_nonzero (TREE_TYPE (gimple_assign_rhs1 (stmt)));
- return true;
-could work, given that most of the pointer ranges are just the simple ones
-perhaps it is too much for little benefit.
-
-2021-11-17 Jakub Jelinek <jakub@redhat.com>
-
- PR tree-optimization/103255
- * gimple-range.cc (fold_using_range::range_of_address): Return
- range_nonzero rather than unadjusted base's range. Formatting fixes.
-
- * gcc.c-torture/execute/pr103255.c: New test.
-
-(cherry picked from commit c39cb6bf835ca12e590eaa6f90222e51be207c50)
----
- gcc/gimple-range.cc | 16 +++++---
- .../gcc.c-torture/execute/pr103255.c | 41 +++++++++++++++++++
- 2 files changed, 52 insertions(+), 5 deletions(-)
- create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr103255.c
-
---- a/gcc/gimple-range.cc
-+++ b/gcc/gimple-range.cc
-@@ -491,14 +491,20 @@ gimple_ranger::range_of_address (irange
- }
- /* If &X->a is equal to X, the range of X is the result. */
- if (off_cst && known_eq (off, 0))
-- return true;
-+ return true;
- else if (flag_delete_null_pointer_checks
- && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (expr)))
- {
-- /* For -fdelete-null-pointer-checks -fno-wrapv-pointer we don't
-- allow going from non-NULL pointer to NULL. */
-- if(!range_includes_zero_p (&r))
-- return true;
-+ /* For -fdelete-null-pointer-checks -fno-wrapv-pointer we don't
-+ allow going from non-NULL pointer to NULL. */
-+ if (!range_includes_zero_p (&r))
-+ {
-+ /* We could here instead adjust r by off >> LOG2_BITS_PER_UNIT
-+ using POINTER_PLUS_EXPR if off_cst and just fall back to
-+ this. */
-+ r = range_nonzero (TREE_TYPE (gimple_assign_rhs1 (stmt)));
-+ return true;
-+ }
- }
- /* If MEM_REF has a "positive" offset, consider it non-NULL
- always, for -fdelete-null-pointer-checks also "negative"
---- /dev/null
-+++ b/gcc/testsuite/gcc.c-torture/execute/pr103255.c
-@@ -0,0 +1,41 @@
-+/* PR tree-optimization/103255 */
-+
-+struct H
-+{
-+ unsigned a;
-+ unsigned b;
-+ unsigned c;
-+};
-+
-+#if __SIZEOF_POINTER__ >= 4
-+#define ADDR 0x400000
-+#else
-+#define ADDR 0x4000
-+#endif
-+#define OFF 0x20
-+
-+int
-+main ()
-+{
-+ struct H *h = 0;
-+ unsigned long o;
-+ volatile int t = 1;
-+
-+ for (o = OFF; o <= OFF; o += 0x1000)
-+ {
-+ struct H *u;
-+ u = (struct H *) (ADDR + o);
-+ if (t)
-+ {
-+ h = u;
-+ break;
-+ }
-+ }
-+
-+ if (h == 0)
-+ return 0;
-+ unsigned *tt = &h->b;
-+ if ((__SIZE_TYPE__) tt != (ADDR + OFF + __builtin_offsetof (struct H, b)))
-+ __builtin_abort ();
-+ return 0;
-+}
case OPT_fconstant_string_class_:
constant_string_class_name = arg;
break;
-@@ -1196,6 +1205,47 @@ c_common_init (void)
+@@ -1198,6 +1207,47 @@ c_common_init (void)
return false;
}
; On SVR4 targets, it also controls whether or not to emit a
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
-@@ -9055,6 +9055,17 @@ This option is only supported for C and
+@@ -9058,6 +9058,17 @@ This option is only supported for C and
@option{-Wall} and by @option{-Wpedantic}, which can be disabled with
@option{-Wno-pointer-sign}.
projects / thirdparty / openwrt.git / commitdiff
