On Wed, Aug 14, 2019 at 11:51:28AM +0530, Tejas Joshi wrote: > > The RTL needs to be something that > > does *not* match the combination of separate operations (just as fma has > > its own RTL, and a separate pass is responsible for converting separate > > So do I need to introduce fadd's own RTL just as fma which would emit > a fused instruction while -ffp-contract is default (fast) and would > emit separate instructions like add in DFmode and then truncate to SF? > while -ffp-contract=off ? (just as fma)
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? A good name for this... I would say "float_contract", because I like horrible names. It shouldn't be hard to think of something better :-) Segher
