PR middle-end/92014 - bogus warning: writing 8 bytes into a region of size 1 in timezone/zic.c
gcc/ChangeLog:
PR middle-end/92014
* tree-ssa-strlen.c (count_nonzero_bytes): Avoid recursing for MEM_REF
again once nbytes has been set .
gcc/testsuite/ChangeLog:
PR middle-end/92014
* gcc.dg/Wstringop-overflow-19.c: New test.
===================================================================
@@ -0,0 +1,27 @@
+/* PR middle-end/92014 - bogus warning: writing 8 bytes into a region
+ of size 1 in timezone/zic.c
+ { dg-do compile }
+ { dg-options "-O2 -Wall" } */
+
+struct
+{
+ char *s1, *s2;
+ char c;
+} z;
+
+
+void f (char **a, int i, int j)
+{
+ char * cp = __builtin_strchr (a[i], '%');
+
+ if (cp && *++cp != 's')
+ return;
+
+ z.s1 = __builtin_strdup (a[i]);
+ if (!z.s1) __builtin_abort ();
+
+ z.s2 = __builtin_strdup (a[j]);
+ if (!z.s2) __builtin_abort ();
+
+ z.c = cp ? *cp : '\0'; // { dg-bogus "\\\[-Wstringop-overflow" }
+}
===================================================================
@@ -3741,13 +3741,16 @@ int ssa_name_limit_t::next_ssa_name (tree ssa_name
return 0;
}
-/* Determine the minimum and maximum number of leading non-zero bytes
+/* Determines the minimum and maximum number of leading non-zero bytes
in the representation of EXP and set LENRANGE[0] and LENRANGE[1]
- to each. Set LENRANGE[2] to the total number of bytes in
- the representation. Set *NULTREM if the representation contains
- a zero byte, and set *ALLNUL if all the bytes are zero. Avoid
- recursing deeper than the limits in SNLIM allow. Return true
- on success and false otherwise. */
+ to each. Sets LENRANGE[2] to the total number of bytes in
+ the representation. Sets *NULTREM if the representation contains
+ a zero byte, and sets *ALLNUL if all the bytes are zero.
+ OFFSET and NBYTES are the offset into the representation and
+ the size of the access to it determined from a MEM_REF or zero
+ for other expressions.
+ Avoid recursing deeper than the limits in SNLIM allow.
+ Returns true on success and false otherwise. */
static bool
count_nonzero_bytes (tree exp, unsigned HOST_WIDE_INT offset,
@@ -3843,6 +3846,9 @@ count_nonzero_bytes (tree exp, unsigned HOST_WIDE_
if (TREE_CODE (exp) == MEM_REF)
{
+ if (nbytes)
+ return false;
+
tree arg = TREE_OPERAND (exp, 0);
tree off = TREE_OPERAND (exp, 1);
@@ -3910,8 +3916,10 @@ count_nonzero_bytes (tree exp, unsigned HOST_WIDE_
lenrange[0] = 0;
prep = NULL;
}
- else
+ else if (!nbytes)
nbytes = repsize;
+ else if (nbytes < repsize)
+ return false;
}
if (!nbytes)