[Bug tree-optimization/17616] New: Micro-optimize tree_code_class

[Bug tree-optimization/17616] New: Micro-optimize tree_code_class

[kazu at cs dot umass dot edu]

We can put IS_EXPR_CODE_CLASS items first in tree_code_class so that
IS_EXPR_CODE_CLASS can be implemented with a single assembly instruction.

That is, the suggested order would be

  tcc_reference,   /* A reference to storage.  */
  tcc_comparison,  /* A comparison expression.  */
  tcc_unary,       /* A unary arithmetic expression.  */
  tcc_binary,      /* A binary arithmetic expression.  */
  tcc_statement,   /* A statement expression, which have side effects
                      but usually no interesting value.  */
  tcc_expression,  /* Any other expression.  */
  tcc_exceptional, /* An exceptional code (fits no category).  */
  tcc_constant,    /* A constant.  */
  tcc_type,        /* A type object code.  */
  tcc_declaration  /* A declaration (also serving as variable refs).  */

Currently, IS_EXPR_CODE_CLASS is effectively implemented as (CLASS - 4) <= 5.

After reordering, we can do CLASS <= 5.

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           Summary: Micro-optimize tree_code_class
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kazu at cs dot umass dot edu
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17616

[Bug tree-optimization/17616] Micro-optimize tree_code_class

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-09-22 21:17 -------
Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |compile-time-hog
   Last reconfirmed|0000-00-00 00:00:00         |2004-09-22 21:17:35
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17616

[Bug tree-optimization/17616] Micro-optimize tree_code_class

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2004-11-15 07:59 -------
How about making the classes bitmasks? 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17616

[Bug tree-optimization/17616] Micro-optimize tree_code_class

[kazu at cs dot umass dot edu]

------- Additional Comments From kazu at cs dot umass dot edu  2004-11-16 17:48 -------
Subject: Re:  Micro-optimize tree_code_class

Hi Steven,

> How about making the classes bitmasks? 

Yes, I came across this idea.  There are a lot of predicates that can
simply use bitmasks.

Kazu Hirata


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17616