[Bug target/79252] New: Improve code generation of vec_insert on PowerPC ISA 2.07 (i.e. power8)

["meissner at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79252

            Bug ID: 79252
           Summary: Improve code generation of vec_insert on PowerPC ISA
                    2.07 (i.e. power8)
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: meissner at gcc dot gnu.org
  Target Milestone: ---

On PowerPC compiles with -mcpu=power8, if you do a vec_insert on vector types
that have 8, 16, or 32-bit element sizes (i.e. char, short, int, float) with a
constant element number, we generate a vector store, element store, and vector
load instead of using a series of instructions instead of generating a
store-hit-load event.