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Re: Expansion of narrowing math built-ins into power instructions


Hi!

On Fri, Aug 23, 2019 at 07:16:59PM +0200, Martin Jambor wrote:
> Therefore, at least for now (GSoC deadline is kind of looming), I
> decided that the best way forward would be to not rely on internal
> functions but plug into expand_builtin() and I wrote the following,
> lightly tested patch - which of course misses testcases and stuff - but
> I'd be curious about any feedback now anyway.  When I proposed a very
> similar approach for the roundeven x86_64 expansion, Uros actually then
> opted for a solution based on internal functions, so I am curious
> whether there are simple alternatives I do not see.
> 
> Tejas, of course cases for other fadd variants should at least be added
> to expand_builtin.

Looks good for the rs6000 part, thanks!  Some trivialities:

> 	* builtins.c (expand_builtin_binary_conversion): New function.
> 	  (expand_builtin): Call it.

(Wrong indentation, should be just one tab, no extra spaces).

> +(define_insn "add_truncdfsf3"
> +  [(set (match_operand:SF 0 "gpc_reg_operand" "=f,wa")
> +	(unspec:SF [(match_operand:DF 1 "gpc_reg_operand" "%d,wa")
> +		    (match_operand:DF 2 "gpc_reg_operand" "d,wa")]
> +		     UNSPEC_ADD_NARROWING))]

Please align the U with the preceding [.


Segher


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