Re: [Patch] MIPS: Add atomic memory operations for QI and HI modes.

[David Daney <ddaney at avtrex dot com>]

David Daney wrote:
> This patch adds support for QI and HI mode atomic memory operations to
> MIPS.  This is a minimal implementation of the QI and HI mode operations
> as it only implements sync_compare_and_swap for those modes.  A possible
> future enhancement would be to implement the full set of atomic insns
> for QI and HI modes, but this should be enough to get libstdc++ building
> again.
>
> The patch borrows from the sparc implementation.
>
> Currently testing on mipsel-linux with all languages,
>
> OK to commit if it tests good?

And it did:

http://gcc.gnu.org/ml/gcc-testresults/2008-04/msg01887.html

This gets us back to clean C++ and libstdc++ test results (except for 
pr31863.C, which times out occasionally when the system is heavily loaded).


> 2008-04-23  David Daney  <ddaney@avtrex.com>
>
>     * config/mips/mips.md (UNSPEC_COMPARE_AND_SWAP_12): New
>     unspec_volitile.
>     (UNSPEC_SYNC_OLD_OP, UNSPEC_SYNC_NEW_OP, UNSPEC_SYNC_EXCHANGE,
>     UNSPEC_MEMORY_BARRIER, UNSPEC_SET_GOT_VERSION,
>     UNSPEC_UPDATE_GOT_VERSION): Renumber.
>     (sync_compare_and_swap<mode>): New expand for QI and HI modes.
>     (compare_and_swap_12): New insn.
>     * config/mips/mips-protos.h (mips_expand_compare_and_swap_12): Declare.
>     * config/mips/mips.c (mips_expand_compare_and_swap_12): New function.
>     * config/mips/mips.h (MIPS_COMPARE_AND_SWAP_12): New macro.