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Re: [PATCHv3] sysdeps/ieee754: prevent maybe-uninitialized errors with -O [BZ #19444]

On Sun, 30 Sep 2018, Martin Jansa wrote:

> +	    /* With GCC 8 (and older) when compiling with -O the compiler
> +	       warns that the variable 'temp', may be used uninitialized.
> +	       The switch above covers all possible values of n & 3
> +	       but GCC without VRP enabled isn't able to figure out the
> +	       range of possible values is [0,3] as explained in:
> +
> +	       so it's false possitive with -O1 and lower. */

"positive" (for all such comments).  Also note there should be two spaces 
at the end of a comment between "." and the trailing "*/".

Are you sure about the "and lower", or is this warning disabled for -O0?  
(glibc disallows building with -O0 at present, but I think we *should* fix 
things to be able to build with -O0, because being able to build with -O0 
would be helpful for debugging - any particular pieces needing 
optimization should then just have it force-enabled, or functions declared 
as always_inline, or whatever is needed, locally.)

Joseph S. Myers

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