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Re: [PATCH v2] Enable inlining issignalingf within glibc


On Mon, 30 Sep 2019, Paul A. Clarke wrote:

> From: "Paul A. Clarke" <pc@us.ibm.com>
> 
> issignalingf is a very small function used in some areas where
> better performance (and smaller code) might be helpful.
> 
> Create inline implementation for issignalingf.
> 
> 2019-09-30  Paul A. Clarke  <pc@us.ibm.com>
> 
> 	* sysdeps/generic/math_private.h (GET_FLOAT_WORD, SET_FLOAT_WORD):
> 	Moved...
> 	* include/math.h (GET_FLOAT_WORD, SET_FLOAT_WORD): to here.
> 	(__issignalingf): New, copied from
> 	sysdeps/iee754/flt-32/s_issignalingf.c.

This is OK.

There's the question of what to do about issignalingf_inline in 
sysdeps/ieee754/flt-32/math_config.h and its uses in 
sysdeps/ieee754/flt-32/e_powf.c.  Arguably they ought to move to just 
calling issignaling.  If however the slightly different code in 
issignalingf_inline results in better code in the callers (which would 
need to be checked, I don't know whether masking or shifting would be 
better in general), that would indicate (a) changing the code in the 
generic inline and (b) filing a GCC bug report to convert one into the 
other as an optimization.

-- 
Joseph S. Myers
joseph@codesourcery.com


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