[Bug middle-end/65346] New: [5 Regression] glibc make check failures since r214941

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65346

            Bug ID: 65346
           Summary: [5 Regression] glibc make check failures since r214941
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org

Another borderline gcc/glibc issue.

Since r214941 the following glibc checks fail:

FAIL: debug/tst-chk3
FAIL: debug/tst-chk6
FAIL: debug/tst-lfschk3
FAIL: debug/tst-lfschk6

trippels@gcc2-power8 debug % gcc -w -std=gnu99 -fgnu89-inline -O2 tst-chk3.i &&
./a.out
/home/trippels/tmp/ccoLyHZS.o: In function `do_test':
tst-chk3.c:(.text+0x2a84): warning: the `gets' function is dangerous and should
not be used.
Test checking routines at fortify level 2
Failure on line 353
Failure on line 357
Failure on line 361
Failure on line 366
Failure on line 370
Failure on line 587
Failure on line 591
Failure on line 595
Hello, World!
Hello, World!
World!
Hello, World!
Hello, World!
World!

trippels@gcc2-power8 debug % cat tst-chk3.c
#define _FORTIFY_SOURCE 2
#include "tst-chk1.c"

from tst-chk1.c:
 345 # if __USE_FORTIFY_LEVEL >= 2
 346 #  define O 0
 347 # else
 348 #  define O 1
 349 # endif
 350
 351   CHK_FAIL_START
 352   strcpy (a.buf1 + (O + 4), str1 + 5);
 353   CHK_FAIL_END
 354
 355   CHK_FAIL_START
 356   p = stpcpy (a.buf1 + (O + 8), str2);
 357   CHK_FAIL_END
 358
 359   CHK_FAIL_START
 360   strncpy (a.buf1 + (O + 6), "X", l0 + 4);
 361   CHK_FAIL_END
 362