Re: c++/7935: floating point test of ">" fails on -O0, not on -O{1,2,3} for certain values double precision float accessed by operator[] in wrapper class (on ix86)

[Richard Henderson <rth@redhat.com>]

The following reply was made to PR c++/7935; it has been noted by GNATS.

From: Richard Henderson <rth@redhat.com>
To: Simon Alexander <sk2alexa@math.uwaterloo.ca>
Cc: rth@gcc.gnu.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
   nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: c++/7935: floating point test of ">"  fails on -O0, not on -O{1,2,3} for certain values double precision float accessed by operator[] in wrapper class (on ix86)
Date: Tue, 17 Sep 2002 08:46:19 -0700

 On Tue, Sep 17, 2002 at 09:12:06AM -0400, Simon Alexander wrote:
 > I am aware of the issues surrounding excess precision.  However, if
 > this is merely a precision issue, can you explain why  it *only* occur
 > when wrapped by a class (not with a raw array), and *only* with -O0 ? 
 
 Your sample set was probably too simple.  With inline accessors, 
 -O0 and a single basic block would be the only time you've got
 a function call between the two computations to force the data
 out of the fp registers.
 
 
 r~