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Re: [PATCH] Optimize abs(x) < 0.0
- From: Gabriel Dos Reis <gdr at integrable-solutions dot net>
- To: Brad Lucier <lucier at math dot purdue dot edu>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: 22 Jul 2002 23:16:02 +0200
- Subject: Re: [PATCH] Optimize abs(x) < 0.0
- Organization: CodeSourcery, LLC
- References: <200207222040.g6MKe7L04442@banach.math.purdue.edu>
Brad Lucier <lucier@math.purdue.edu> writes:
[...]
| > The proposed transformation doesn't preserve semantics in presence
| > of signaling NaNs. I suggest it to be applied only either unsafe-math
| > or say -fno-nan-values or whatever.
|
| There is an option -fno-trapping-math that tells the compiler that
| the libraries are set up to do no trapping of floating-point arithmetic;
| perhaps the transformation should be predicated on this flag.
That is indeed a good suggestion. Roger is working on a flag
-fsignaling-nan, maybe be they could be combined, say
-fno-trapping-math implying -fno-signaling-nan?
-- Gaby