c++/4706: ICE with -O2{3} -funroll-loops -ffast-math

c++/4706: ICE with -O2{3} -funroll-loops -ffast-math

[pcarlini]

>Number:         4706
>Category:       c++
>Synopsis:       ICE with -O2{3} -funroll-loops -ffast-math
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-legal-code
>Submitter-Id:   net
>Arrival-Date:   Fri Oct 26 14:56:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Paolo Carlini / Charles Leggett
>Release:        3.1 20011026 (experimental)
>Organization:
>Environment:
i686-pc-linux-gnu (PII, Linux2.4.10)
>Description:
The attached testcode triggers an ICE when compiling with
-O2 (or -O3) -funroll-loops -ffast-math, i.e.:

ICE.cpp: In member function `void point_mass_class::acceleration(double,
   double*, double (&)[4])':
ICE.cpp:79: Internal compiler error in emit_swap_insn, at reg-stack.c:988


>How-To-Repeat:
3.0.2 and 2.95.x are ok.
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: application/octet-stream; name="ICE.cpp"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="ICE.cpp"
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