[Bug tree-optimization/112661] [14] RISC-V ICE: in duplicate_and_interleave, at tree-vect-slp.cc:8025 with maxval_char_3.f90 vlen256b since r14-5101-g60034ecf25597b

[rsandifo at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112661

--- Comment #8 from Richard Sandiford <rsandifo at gcc dot gnu.org> ---
I think we're going down the wrong path here.  If I've understood
the original change correctly, dummy masks aren't special because
they're masks.  They're special because all elements are equal to
the same value.  A mask such as:

  { 1, 1, 1, 0, 1 }

would not be OK, just like an integer vector with those values would
not be OK.

So IMO we should check whether all elements are equal, rather than
whether the type is one thing or another.