tree-optimization/112623 - forwprop VEC_PACK_TRUNC generation
For vec_pack_trunc patterns there can be an ambiguity for the
source mode for BFmode vs HFmode. The vectorizer checks
the insns operand mode for this, the following makes forwprop
do the same. That of course doesn't help if the target supports
both conversions.
PR tree-optimization/112623
* tree-ssa-forwprop.cc (simplify_vector_constructor):
Check the source mode of the insn for vector pack/unpacks.
* gcc.target/i386/pr112623.c: New testcase.