[Bug target/44995] New: define a macro for presence of -mregnames option

[Bug target/44995] New: define a macro for presence of -mregnames option

[fche at redhat dot com]

In some cases, it would be useful if the presence of the gcc -mregnames
option was not only communicated to the assembler, but also to the C
program being compiled.  This comes up in an unusual usage of
inline-assembler operands, where the ambiguity between literals and
register names is a problem.  (http://sourceware.org/PR11821).
With such a macro (say, -D__GCC_REGNAMES), the inline-asm code could
emit extra code strings to allow resolution of the ambiguities.


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           Summary: define a macro for presence of -mregnames option
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: fche at redhat dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44995

[Bug target/44995] define a macro for presence of -mregnames option

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2010-07-19 21:48 -------
>ambiguity
It is not ambiguous at all in correct usage of inline-asm.  I don't support a
macro for this option at all.


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
 GCC target triplet|                            |powerpc*-*-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44995

[Bug target/44995] define a macro for presence of -mregnames option

[fche at redhat dot com]

------- Comment #2 from fche at redhat dot com  2010-07-19 21:51 -------
> It is not ambiguous at all in correct usage of inline-asm.

Well, considering that the "g" constraint can generate either a literal or
a naked register number, the ambiguity is real even for normal inline assembly.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44995

[Bug target/44995] define a macro for presence of -mregnames option

[fche at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44995

--- Comment #4 from Frank Ch. Eigler <fche at redhat dot com> 2011-08-19 11:24:19 UTC ---
We have worked around this powerpc oddity in systemtap's recent sdt.h
versions by using both %0 and %I0 together to get a special markup for
literals vs. register names.

[Bug target/44995] define a macro for presence of -mregnames option

[jan.kratochvil at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44995

Jan Kratochvil <jan.kratochvil at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jan.kratochvil at redhat
                   |                            |dot com

--- Comment #3 from Jan Kratochvil <jan.kratochvil at redhat dot com> 2011-08-19 08:05:07 UTC ---
This seems to be now related to PR 32998 -grecord-gcc-switches although that
works only with DWARF, -frecord-gcc-switches cannot differentiate between CUs.