[Bug c++/56715] Explicit Reg Vars are being ignored for consts when using g++

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56715

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-03-25 08:50:15 UTC ---
Simply don't use const on the register asm vars for C++.  The thing is that
already the C++ frontend is replacing all the r4 const var uses with just
0x1000 (i.e. the initializer), that isn't really an optimization, but part of
C++ semantics.  r4 is an integral constant expression that evaluates to 0x1000.
 See
ISO C++ 98, [expr.const]/1.  So in foo what you are doing is actually
void foo() {
    register const int r4 asm("r4") = 0x1000;
    asm volatile("swi #1" : : "r"(0x1000));
}
and that of course can use any available register.