Only emulate integral vectors.

Only emulate integral vectors.

The emulation via word mode tries to perform integer arithmetic on floating
point values instead of floating point arithmetic.  This leads to
mis-compilations.

Failure occured on s390x on these existing test cases:
gcc.dg/vect/tsvc/vect-tsvc-s112.c
gcc.dg/vect/tsvc/vect-tsvc-s113.c
gcc.dg/vect/tsvc/vect-tsvc-s119.c
gcc.dg/vect/tsvc/vect-tsvc-s121.c
gcc.dg/vect/tsvc/vect-tsvc-s131.c
gcc.dg/vect/tsvc/vect-tsvc-s132.c
gcc.dg/vect/tsvc/vect-tsvc-s2233.c
gcc.dg/vect/tsvc/vect-tsvc-s421.c
gcc.dg/vect/vect-alias-check-14.c
gcc.target/s390/vector/partial/s390-vec-length-epil-run-1.c
gcc.target/s390/vector/partial/s390-vec-length-epil-run-3.c
gcc.target/s390/vector/partial/s390-vec-length-full-run-3.c

gcc/ChangeLog:

	PR tree-optimization/114075

	* tree-vect-stmts.cc (vectorizable_operation): Don't emulate floating
	point vectors

Signed-off-by: Juergen Christ <jchrist@linux.ibm.com>