[Bug target/82981] [7/8 Regression] unnecessary __multi3 call for mips64r6 linux kernel

[wilson at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981

--- Comment #7 from Jim Wilson <wilson at gcc dot gnu.org> ---
      if (GET_MODE_2XWIDER_MODE (mode).exists (&wmode)
          && targetm.scalar_mode_supported_p (wmode))
This test succeeds, and then in expand_expr WIDEN_MULT_EXPR the checks for a
mult widen optab entry fails, so it gnerates a TImode multiply, which is a
libcall.