Now the pos for fetching an out info is checked in all cases.

This fixes backend/amd64_sub2.c.

There is only an fstp variant for storing 80bit float values. Introduce
a special fstp node so we can already create the the fixup copies in the
spillprepare phase.

There is only the fistp variant for 64bit integer stores. Introduce a
special fistp node so we can already create the fixup copies in the
spillprepare phase and avoid the fixup code in the x87 simulator which
was also wrong for the fist case.

The kills value constraint indicated that the value in a register is
modified after it is read. A copy is inserted if the value is still
required after a kills_value use.

Properly use get_irn_pinned/set_irn_pinned as bool value instead of
comparing setting the ir_op enum values.

bescripts: Use the single register requirements provided by regalloc instead of generating duplicate ones for new nodes.

bescripts: Use the class requirements provided by regalloc instead of generating duplicate ones for new nodes.

The generator chooses the right default automatically.

All backends had identical implementations.
Now rematerialization works out of the box for new backends.

Now add_pressure[] is copied.

Actually, I just want to trigger the buildbot and see if my fix worked.

Avoid using the op_pin_state enum as that contains confusing additional
entries that are not valid on a node. The only remaining state for a
node is pinned/floating which we can simply represent with a 0/1 value.

I can't explain why the copy was created there, the comment explaining
it makes no sense.

This case cannot happen anymore nowadays, instead we have some code that
turns CopyKeeps into Keeps after the SSA reconstruction there.

This adds two builtin kinds, ir_bk_va_start and ir_bk_va_arg. va_arg Builtins
are lowered in the lower_builtins pass with a function provided by the backend,
whereby most architectures can use be_default_lower_va_args. va_start Builtins
are lowered in the backend.

Note: This commit breaks all backends except for IA32. SPARC and AMD64 are
implemented in later commits. The ARM backend previously miscompiled variadic
functions, and will now throw a proper error.

All backends have similar empty Start nodes, which just provide registers.
So having one generic backend Start node to share some infrastructure is sensible.