Generalize compute_objsize to return maximum size/offset instead of failing (PR middle-end/97023).

Also resolves:
PR middle-end/97342 - bogus -Wstringop-overflow with nonzero signed and unsigned offsets
PR middle-end/97023 - missing warning on buffer overflow in chained mempcpy
PR middle-end/96384 - bogus -Wstringop-overflow= storing into multidimensional array with index in range

gcc/ChangeLog:

	PR middle-end/97342
	PR middle-end/97023
	PR middle-end/96384
	* builtins.c (access_ref::access_ref): Initialize new member.  Use
	new enum.
	(access_ref::size_remaining): Define new member function.
	(inform_access): Handle expressions referencing objects.
	(gimple_call_alloc_size): Call get_size_range instead of get_range.
	(gimple_call_return_array): New function.
	(get_range): Rename...
	(get_offset_range): ...to this.  Improve detection of ranges from
	types of expressions.
	(gimple_call_return_array): Adjust calls to get_range per above.
	(compute_objsize): Same.  Set maximum size or offset instead of
	failing for unknown objects and handle more kinds of expressions.
	(compute_objsize): Call access_ref::size_remaining.
	(compute_objsize): Have transitional wrapper fail for pointers
	into unknown objects.
	(expand_builtin_strncmp): Call access_ref::size_remaining and
	handle new cases.
	* builtins.h (access_ref::size_remaining): Declare new member function.
	(access_ref::set_max_size_range): Define new member function.
	(access_ref::add_ofset, access_ref::add_max_ofset): Same.
	(access_ref::add_base0): New data member.
	* calls.c (get_size_range): Change argument type.  Handle new
	condition.
	* calls.h (get_size_range): Adjust signature.
	(enum size_range_flags): Define new type.
	* gimple-ssa-warn-restrict.c (builtin_memref::builtin_memref): Correct
	argument to get_size_range.
	* tree-ssa-strlen.c (get_range): Handle anti-ranges.
	(maybe_warn_overflow): Check DECL_P before assuming it's one.

gcc/testsuite/ChangeLog:

	PR middle-end/97342
	PR middle-end/97023
	PR middle-end/96384
	* c-c++-common/Wrestrict.c: Adjust comment.
	* gcc.dg/Wstringop-overflow-34.c: Remove xfail.
	* gcc.dg/Wstringop-overflow-43.c: Remove xfails.  Adjust regex patterns.
	* gcc.dg/pr51683.c: Prune out expected warning.
	* gcc.target/i386/pr60693.c: Same.
	* g++.dg/warn/Wplacement-new-size-8.C: New test.
	* gcc.dg/Wstringop-overflow-41.c: New test.
	* gcc.dg/Wstringop-overflow-44.s: New test.
	* gcc.dg/Wstringop-overflow-45.c: New test.
	* gcc.dg/Wstringop-overflow-46.c: New test.
	* gcc.dg/Wstringop-overflow-47.c: New test.
	* gcc.dg/Wstringop-overflow-49.c: New test.
	* gcc.dg/Wstringop-overflow-50.c: New test.
	* gcc.dg/Wstringop-overflow-51.c: New test.
	* gcc.dg/Wstringop-overflow-52.c: New test.
	* gcc.dg/Wstringop-overflow-53.c: New test.
	* gcc.dg/Wstringop-overflow-54.c: New test.
	* gcc.dg/Wstringop-overflow-55.c: New test.
	* gcc.dg/Wstringop-overread-5.c: New test.

1 files changed, 13 insertions, 1 deletions

diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
index f4d1c5c..ebb17cd 100644
--- a/gcc/tree-ssa-strlen.c
+++ b/gcc/tree-ssa-strlen.c
@@ -228,8 +228,20 @@ get_range (tree val, gimple *stmt, wide_int minmax[2],
 
   value_range_kind rng = get_range_info (val, minmax, minmax + 1);
   if (rng == VR_RANGE)
+    /* This may be an inverted range whose MINMAX[1] < MINMAX[0].  */
     return val;
 
+  if (rng == VR_ANTI_RANGE)
+    {
+      /* An anti-range is the same as an ordinary range with inverted
+	 bounds (where MINMAX[1] < MINMAX[0] is true) that may result
+	 from the conversion of a signed anti-range to unsigned.  */
+      wide_int tmp = minmax[0];
+      minmax[0] = minmax[1] + 1;
+      minmax[1] = wi::sub (tmp, 1);
+      return val;
+    }
+
   /* Do not handle anti-ranges and instead make use of the on-demand
      VRP if/when it becomes available (hopefully in GCC 11).  */
   return NULL_TREE;
@@ -2243,7 +2255,7 @@ maybe_warn_overflow (gimple *stmt, tree len,
     sprintf (offstr, "[%lli, %lli]",
 	     (long long) offrng[0].to_shwi (), (long long) offrng[1].to_shwi ());
 
-  if (destdecl)
+  if (destdecl && DECL_P (destdecl))
     {
       if (tree size = DECL_SIZE_UNIT (destdecl))
 	inform (DECL_SOURCE_LOCATION (destdecl),