This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]

Re: egcs-1.2 stuff


>>   In message <m10O2ic-000ErMC@ocean.lucon.org>you write:
>>   > I enabled all TARGET_CMOVE and CC_FCOMI. I also optimized the fp
>>   > cmove.
>>   > 
>>   > What do you mean by that? I sent in patches months ago and you said
>>   > you would take a look. What happened?
>> The FCOMI stuff I explicitly left with you and John to sort out.  Last I
>> heard there were still technical problems with that patch.  If you and John
>> think the patch is done, then send the final patch.
>> 
>
> This is the latest patch I have been using. It seems ok.

This patch seems to include several unrelated patches which makes it harder
to review.

  1) I have no objection to:

	* config/i386/i386.c (notice_update_cc): No need to check the
	INT mode for conditional moves since FLOAT conditional moves
	don't affect cc0.

      x86 floating point conditional moves do change the FP status
      register, however gcc is currently unaware of this register.

  2) The change:

        (output_fp_conditional_move): Abort for LT, LE, GE, and GT
        signed integer comparisons.

     shouldn't be necessary since the floating point conditional move
     expander will never generate LT, LE, GE, or GT signed integer
     comparisons.  It's useful if we want a belt and suspenders approach.

  3) I have no objection to:

	(output_int_conditional_move): Use "enum rtx_code" for code
	type.

  4) I am currently rewriting various floating point patterns (including
     compare) and prefer to deal with the FCOMI and FP conditional move
     issues as part of the rewrite.  The floating point compare patterns
     do way too many things behind the scenes.  Your change to support
     FCOMI may be okay (I haven't looked closely), however it does leave
     gcc believing that that AX register is clobbered (which isn't true
     when FCOMI is used and ! IEEE).

-- John
-------------------------------------------------------------------------
|   Feith Systems  |   Voice: 1-215-646-8000  |  Email: john@feith.com  |
|    John Wehle    |     Fax: 1-215-540-5495  |                         |
-------------------------------------------------------------------------



Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]