FYI: New warning occurring during 'make'

I'm seeing a new warning during 'make' in blead:

`sh  cflags "optimize='-Os -pipe -funit-at-a-time -march=pentium4
-mfpmath=sse -mieee-fp -mmmx -msse -msse2'" sv.o`  sv.c
	  CCCMD =  gcc -DPERL_CORE -c -DPERL_USE_SAFE_PUTENV
-U__STRICT_ANSI__ -DNO_MATHOMS -fno-strict-aliasing -pipe  -Os -pipe
-funit-at-a-time -march=pentium4 -mfpmath=sse -mieee-fp -mmmx -msse
-msse2 -Wall -W -Wextra -Wdeclaration-after-statement -Wendif-labels
sv.c: In function `Perl_ss_dup':
sv.c:11589: warning: operation on `ix' may be undefined

I looked at the code, but can't tell what's causing this - too many
macros to determine the culprit.

• FYI: New warning occurring during 'make' by Jerry D. Hedden
• Re: FYI: New warning occurring during 'make' by Vincent Pit