[Bug c++/61294] New: [4.9 Regression] erroneous memset used with constant zero length parameter warning

["orion at cora dot nwra.com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61294

            Bug ID: 61294
           Summary: [4.9 Regression] erroneous memset used with constant
                    zero length parameter warning
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: orion at cora dot nwra.com

Created attachment 32846
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=32846&action=edit
preprocessed test case

$ g++ -std=c++11 -O2 -c test.cxx
In function 'void* memset(void*, int, size_t)',
    inlined from 'static void
vtkDistributedDataFilter::AddConstantUnsignedCharPointArray(vtkUnstructuredGrid*,
const char*, unsigned char)' at test.cxx:31883:29:
test.cxx:15303:32: warning: call to '__warn_memset_zero_len' declared with
attribute warning: memset used with constant zero length parameter; this could
be due to transposed parameters
       __warn_memset_zero_len ();
                                ^

# g++ -v
Using built-in specs.
COLLECT_GCC=/usr/bin/g++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.9.0/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla
--enable-bootstrap --enable-shared --enable-threads=posix
--enable-checking=release --enable-multilib --with-system-zlib
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object
--enable-linker-build-id --with-linker-hash-style=gnu
--enable-languages=c,c++,objc,obj-c++,fortran,ada,go,lto --enable-plugin
--enable-initfini-array --disable-libgcj
--with-isl=/builddir/build/BUILD/gcc-4.9.0-20140518/obj-x86_64-redhat-linux/isl-install
--with-cloog=/builddir/build/BUILD/gcc-4.9.0-20140518/obj-x86_64-redhat-linux/cloog-install
--enable-gnu-indirect-function --with-tune=generic --with-arch_32=i686
--build=x86_64-redhat-linux
Thread model: posix
gcc version 4.9.0 20140518 (Red Hat 4.9.0-5) (GCC)

No warning with 4.8.2 (or without -O2)