[PATCH] Improves __ieee754_exp() performance by greater than 5x on sparc/x86.

[Joseph Myers]

On Thu, 26 Oct 2017, Joseph Myers wrote:

> Unless a particular constant, table etc. is needed in the code both as 
> integers and as double, just define it as double and initialize with a C99 
> hex float constant, without involving unions at all.  This certainly 
> applies to some of your constants, possibly all of them.

To be clear: all my past and present comments about hex floats always mean 
C99 0x1.2p3 and similar constants.  Never hex integer values with a union 
as in this patch.  You should never, anywhere in glibc, have any occasion 
to initialize a floating-point constant via specifying the integer values 
of its representation (except in testcases for special ldbl-96 and 
ldbl-128ibm representations).  Proper hex floating-point constants are 
always better.

-- 
Joseph S. Myers
joseph@codesourcery.com