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Re: [PATCH] string/stratcliff.c: Replace int with size_t [BZ #21982]
- From: Stefan Liebler <stli at linux dot vnet dot ibm dot com>
- To: libc-alpha at sourceware dot org
- Date: Mon, 21 Aug 2017 15:48:04 +0200
- Subject: Re: [PATCH] string/stratcliff.c: Replace int with size_t [BZ #21982]
- Authentication-results: sourceware.org; auth=none
- References: <20170820171713.GA19531@gmail.com>
On 08/20/2017 07:17 PM, H.J. Lu wrote:
Fix GCC 7 errors when string/stratcliff.c is compiled with -O3:
stratcliff.c: In function ‘do_test’:
cc1: error: assuming signed overflow does not occur when assuming that (X - c) <= X is always true [-Werror=strict-overflow]
OK for master?
* string/stratcliff.c (do_test): Declare size, nchars, inner,
middle and outer with size_t instead of int. Repleace %d with
%Zd in printf.
string/stratcliff.c | 72 ++++++++++++++++++++++++++---------------------------
1 file changed, 36 insertions(+), 36 deletions(-)
diff --git a/string/stratcliff.c b/string/stratcliff.c
index e28b0c5058..ae780379cb 100644
@@ -58,8 +58,8 @@
- int size = sysconf (_SC_PAGESIZE);
- int nchars = size / sizeof (CHAR);
+ size_t size = sysconf (_SC_PAGESIZE);
+ size_t nchars = size / sizeof (CHAR);
int result = 0;
@@ -80,7 +80,7 @@ do_test (void)
- int inner, middle, outer;
+ size_t inner, middle, outer;
mprotect (adr, size, PROT_NONE);
mprotect (adr + 2 * nchars, size, PROT_NONE);
@@ -101,7 +101,7 @@ do_test (void)
if (STRLEN (&adr[outer]) != (size_t) (inner - outer))
- printf ("%s flunked for outer = %d, inner = %d\n",
+ printf ("%s flunked for outer = %Zd, inner = %Zd\n",
STRINGIFY (STRLEN), outer, inner);
result = 1;
- printf ("%s flunked for outer = %d, middle = %d\n",
+ printf ("%s flunked for outer = %Zd, middle = %Zd\n",
STRINGIFY (rawmemchr), outer, middle);
result = 1;
Hi H.J. Lu,
I've applied your patch and the warnings does not occur anymore on s390.
The outer loops of the string tests are all using the following:
size_t nchars, outer;
for (outer = nchars - 1; outer >= MAX (0, nchars - 128); --outer)
I think we can assume, that nchars is always > 128 as it is derived by
But if nchars would be equal to 128, this would result in an infinite
loop (outer >= 0)?
If nchars would be less than 128, the tests would be skipped.
Should we add a check that nchars > 128 at the beginning and replace the
"MAX (0, nchars - 128)" with only "nchars - 128"?