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[Bug tree-optimization/52907] Underflowing floating point expressions wrongly folded to zero
- From: "joseph at codesourcery dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 23 Apr 2012 20:02:50 +0000
- Subject: [Bug tree-optimization/52907] Underflowing floating point expressions wrongly folded to zero
- Auto-submitted: auto-generated
- References: <bug-52907-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52907
--- Comment #2 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2012-04-23 20:02:50 UTC ---
On Tue, 10 Apr 2012, rguenth at gcc dot gnu.org wrote:
> Does real.c even communicate this fact?
You can identify underflow from the result of multiplication or division
being zero or subnormal (unless an operand is zero or infinite), just as
overflow is identified from an infinite result. Information about
subnormal results may not be conveniently communicated by real.c, but
simply handling zero results here would be enough for the use cases in
glibc.