Description of problem:

memchr(ptr,c,0) makes a memory access to *ptr. But according to ISO C 99, memchr(ptr,c,n) must only access the n bytes starting at ptr, not the n+1 bytes starting at ptr. For n=0, it means no memory access to *ptr at all.

Version-Release number of selected component (if applicable):


How reproducible:

Compile and run the attached program.

Steps to Reproduce:
1. gcc -O -Wall memchr-bug.c
2. ./a.out
  
Actual results:

Segfaults inside memchr:

    memchr () at ../sysdeps/x86_64/memchr.S:31
    31              movdqa  (%rdi), %xmm0

Expected results:

Exits normally with exit code 0.

Additional info:

This may be the same bug as
https://bugzilla.redhat.com/show_bug.cgi?id=499705

A related but different issue is
https://bugzilla.redhat.com/show_bug.cgi?id=499689