[Bug target/99645] New: pdp-11 target produces inefficient code for sign extend

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99645

            Bug ID: 99645
           Summary: pdp-11 target produces inefficient code for sign
                    extend
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pkoning at gcc dot gnu.org
  Target Milestone: ---

This issue was revealed by bug 84437.  The reproducer given there now produces
"correct" code but it's quite inefficient because it uses a shift by 15 for
sign extend.  On pdp11 that's not the best answer.