On Wed, 14 Aug 2019, Segher Boessenkool wrote: > I think you can do one RTL code that replaces float_truncate in > > > > > > (define_insn "add_truncdfsf3" > > > > > [(set (match_operand:SF 0 "gpc_reg_operand" "=f,wa") > > > > > (float_truncate:SF > > > > > (plus:DF (match_operand:DF 1 "gpc_reg_operand" "%d,wa") > > > > > (match_operand:DF 2 "gpc_reg_operand" "d,wa"))))] > > but that is only meant for such explicit contraction. This can then > happily be used to implement all such patterns. Is there some issue > with that I overlook?
Yes, I think such a separate RTL code would work (as would an architecture-specific UNSPEC) - it just needs to avoid the pattern matching RTL that can arise other than from the built-in functions. (Everything to do with needing -fno-math-errno to expand into such instructions should be handled in the architecture-independent compiler.) -- Joseph S. Myers jos...@codesourcery.com
