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Re: rs6000 LDBL_MAX converts to infinity
On Thu, Mar 04, 2004 at 06:38:31PM +1030, Alan Modra wrote:
> * real.c (encode_ibm_extended): Don't bother rounding low double.
I blew it. There's another reason to call round_for_format here, and
that's to handle denormals. Without the round_for_format call we
can pass encode_ieee_double an exponent that's too negative, and
it will merrily wrap around to a large positive exponent.
A testcase is a value like __LDBL_MIN__ + __LDBL_DENORM_MIN__.
This reverts my previous patch and adds a comment explaining
why round_for_format is called.
* real.c (encode_ibm_extended): Do round low word.
Applying mainline. Mark, this needs to go on the branch too please.
RCS file: /cvs/gcc/gcc/gcc/real.c,v
retrieving revision 1.139
diff -u -p -r1.139 real.c
--- gcc/real.c 4 Mar 2004 10:23:20 -0000 1.139
+++ gcc/real.c 11 Mar 2004 13:28:12 -0000
@@ -3248,9 +3248,8 @@ encode_ibm_extended (const struct real_f
if (u.class == rvc_normal)
do_add (&v, &normr, &u, 1);
- /* The low double won't need rounding, since we round to a 106 bit
- mantissa before calling this function, and we've just
- subtracted off the top 54 bits. (53+1 because u is rounded.) */
+ /* Call round_for_format since we might need to denormalize. */
+ round_for_format (base_fmt, &v);
encode_ieee_double (base_fmt, &buf, &v);
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