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From: "joseph at codesourcery dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/105376] ICE: in decimal_to_decnumber, at
 dfp.cc:134 with _Decimal128 at -O -g
Date: Tue, 26 Apr 2022 17:56:02 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105376

--- Comment #3 from joseph at codesourcery dot com <joseph at codesourcery =
dot com> ---
For this transformation to be correct for DFP, you need a 2 with quantum=20
exponent 0.  Converting from either integer or binary floating-point 2=20
will work for that.  However, I note that decimal_to_decnumber has

    case rvc_normal:
      if (!r->decimal)
        {
          /* dconst{1,2,m1,half} are used in various places in
             the middle-end and optimizers, allow them here
             as an exception by converting them to decimal.  */

so the existing code ought to work as-is.  Maybe there is a problem with=20
padding in REAL_VALUE_TYPE meaning the comparisons don't work as intended?=