[Bug tree-optimization/39129] New: The meaning of 'BB' in "too many BBs in loop"

[Bug tree-optimization/39129] New: The meaning of 'BB' in "too many BBs in loop"

[lanurmi at iki dot fi]

Compile something with -ftree-vectorizer-verbose, and you'll probably get:

"note: not vectorized: too many BBs in loop."

The meaning of 'BB' in this context is most certainly not universally known, so
instead of a mysterious two-letter acronym the warning should talk about basic
blocks.

(I couldn't even find out the meaning of 'BB' by using Google, then I ended up
asking on IRC.)


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           Summary: The meaning of 'BB' in "too many BBs in loop"
           Product: gcc
           Version: 4.3.2
            Status: UNCONFIRMED
          Severity: trivial
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: lanurmi at iki dot fi


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2009-02-08 10:23 -------
Confirmed.  Even spelling out "basic-block" here isn't going to be too useful
to the occasional programmer.  I know that it is sometimes even just a
non-empty latch block that triggers this, so even "control flow in loop"
wouldn't be entirely correct (but may, in more complex cases, hint at the
source of the problem).


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |irar at gcc dot gnu dot org,
                   |                            |dorit at gcc dot gnu dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |diagnostic
   Last reconfirmed|0000-00-00 00:00:00         |2009-02-08 10:23:25
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2009-02-26 23:35 -------
BB is a copy acronym in computer science.  And Basic block is a common term in
compilers.  Really this warning is not useful for most users anyways.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|trivial                     |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[lanurmi at iki dot fi]

------- Comment #3 from lanurmi at iki dot fi  2009-02-27 20:15 -------
Well yes, the meaning of basic block is not self-explanatory either.  But at
least it is a much better search term than just 'BB'.  And if someone comes up
with something even better, I'm certainly not against it.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[irar at il dot ibm dot com]

------- Comment #4 from irar at il dot ibm dot com  2009-05-31 10:55 -------
So, will "too many basic blocks in loop" be good enough? Because this is what
it is, the reason that the loop form is not suitable for the vectorizer is that
there are too many basic blocks in it.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2009-05-31 12:14 -------
Definitely spelling out basic-block is an improvement.  Though it would be nice
to use 'control-flow' when appropriate, if we can exclude the non-empty
latch case from this.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[irar at il dot ibm dot com]

------- Comment #6 from irar at il dot ibm dot com  2009-05-31 12:33 -------
For non-empty latch block we actually print "not vectorized: unexpected loop
form." So I can change it to "not vectorized: non-empty latch block", and
instead of "too many BBs" I can write "control flow in loop". 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[rguenth at gcc dot gnu dot org]

------- Comment #7 from rguenth at gcc dot gnu dot org  2009-05-31 15:27 -------
I see.  Unexpected loop form is better for the user I guess, so just change
the other part.  Thx.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[irar at gcc dot gnu dot org]

------- Comment #8 from irar at gcc dot gnu dot org  2009-06-01 08:15 -------
Subject: Bug 39129

Author: irar
Date: Mon Jun  1 08:15:01 2009
New Revision: 148036

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=148036
Log:

        PR tree-optimization/39129
        * tree-vect-loop-manip.c (conservative_cost_threshold): Change the 
        printed message.
        (vect_do_peeling_for_loop_bound): Use 
        LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT and
        LOOP_REQUIRES_VERSIONING_FOR_ALIAS macros.
        (vect_loop_versioning): Likewise.
        (vect_create_cond_for_alias_checks): Fix indentation.
        * tree-vectorizer.h (struct _loop_vec_info): Fix indentation of the 
        macros.
        (LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT): Define.
        (LOOP_REQUIRES_VERSIONING_FOR_ALIAS): Likewise.
        * tree-vect-loop.c (vect_analyze_loop_form): Change "too many BBs" to 
        "control flow in loop".
        (vect_estimate_min_profitable_iters): Use 
        LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT and
        LOOP_REQUIRES_VERSIONING_FOR_ALIAS macros.
        * tree-vect-data-refs.c (vect_enhance_data_refs_alignment): Likewise.
        (vect_create_data_ref_ptr): Don't mention array dimension in printing.
        * tree-vect-stmts.c (vectorizable_store): Replace the check that the 
        statement belongs to a group of strided accesses with the exact code 
        check.
        (vectorizable_load): Likewise.
        * tree-vect-slp.c (vect_analyze_slp_instance): Spell out "basic block".
        (vect_slp_analyze_bb, vect_slp_transform_bb): Likewise.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-vect-data-refs.c
    trunk/gcc/tree-vect-loop-manip.c
    trunk/gcc/tree-vect-loop.c
    trunk/gcc/tree-vect-slp.c
    trunk/gcc/tree-vect-stmts.c
    trunk/gcc/tree-vectorizer.h


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129

[Bug tree-optimization/39129] The meaning of 'BB' in "too many BBs in loop"

[irar at il dot ibm dot com]

------- Comment #9 from irar at il dot ibm dot com  2009-06-01 08:20 -------
Fixed.


-- 

irar at il dot ibm dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39129