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bug#5754: Bytecomp Arithmetic test failed
From: |
Chong Yidong |
Subject: |
bug#5754: Bytecomp Arithmetic test failed |
Date: |
Sat, 03 Apr 2010 19:31:57 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1.95 (gnu/linux) |
Juri Linkov <juri@jurta.org> writes:
> Does (let ((a (expt 2 -1074)) (b 0.125)) (* a b 8))
> return 5e-324 when you compile with CFLAGS="-g -O2"?
With CFLAGS="-g -O2",
(let ((a (expt 2 -1074)) (b 0.125)) (* a b 8))
=> 5e-24
(eval '(let ((a (expt 2 -1074)) (b 0.125)) (* a 8 b)))
=> 5e-324
(funcall (byte-compile
(list 'lambda nil
(quote (let ((a (expt 2 -1074)) (b 0.125)) (* a 8 b))))))
=> 5e-24
With CFLAGS="-g",
(let ((a (expt 2 -1074)) (b 0.125)) (* a b 8))
=> 0.0
(eval '(let ((a (expt 2 -1074)) (b 0.125)) (* a 8 b)))
=> 5e-324
(funcall (byte-compile
(list 'lambda nil
(quote (let ((a (expt 2 -1074)) (b 0.125)) (* a 8 b))))))
=> 0.0
The latter two are what cause bytecomp-testsuite to fail.