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* [PATCH][RFC] Gate loop passes group on number-of-loops > 1, add no-loops group
@ 2014-06-18 10:44 Richard Biener
  2014-06-18 10:54 ` Jakub Jelinek
  2014-06-18 13:38 ` Jeff Law
  0 siblings, 2 replies; 4+ messages in thread
From: Richard Biener @ 2014-06-18 10:44 UTC (permalink / raw)
  To: gcc-patches


The following aims at reducing the number of pointless passes we run
on functions containing no loops.  Those are at least two copyprop
and one dce pass (two dce passes when vectorization is enabled,
three dce passes and an additional copyprop pass when any graphite
optimization is enabled).

Simply gating pass_tree_loop on number_of_loops () > 1 would disable
basic-block vectorization on loopless functions.  Moving
basic-block vectorization out of pass_tree_loop works to the extent
that you'd need to move IVOPTs as well as data-ref analysis cannot
cope with TARGET_MEM_REFs.

So the following introduces a pass_tree_no_loop pass group which
is enabled whenever the pass_tree_loop group is disabled.
As followup this would allow to skip cleanup work we do after the loop
pipeline just to cleanup after it.

Any comments?  Does such followup sound realistic or would it be
better to take the opportunity to move IVOPTs a bit closer to
RTL expansion and avoid that "pass_tree_no_loop hack"?

Bootstrap and regtest running on x86_64-unknown-linux-gnu.

Thanks,
Richard.

2014-06-18  Richard Biener  <rguenther@suse.de>

	* tree-ssa-loop.c (gate_loop): New function.
	(pass_tree_loop::gate): Call it.
	(pass_data_tree_no_loop, pass_tree_no_loop,
	make_pass_tree_no_loop): New.
	* tree-vectorizer.c: Include tree-scalar-evolution.c
	(pass_slp_vectorize::execute): Initialize loops and SCEV if
	required.
	(pass_slp_vectorize::clone): New method.
	* timevar.def (TV_TREE_NOLOOP): New.
	* tree-pass.h (make_pass_tree_no_loop): Declare.
	* passes.def (pass_tree_no_loop): New pass group with
	SLP vectorizer.

Index: gcc/tree-ssa-loop.c
===================================================================
*** gcc/tree-ssa-loop.c.orig	2014-06-18 12:06:19.226205380 +0200
--- gcc/tree-ssa-loop.c	2014-06-18 12:06:39.103204012 +0200
*************** along with GCC; see the file COPYING3.
*** 42,47 ****
--- 42,63 ----
  #include "diagnostic-core.h"
  #include "tree-vectorizer.h"
  
+ 
+ /* Gate for loop pass group.  The group is controlled by -ftree-loop-optimize
+    but we also avoid running it when the IL doesn't contain any loop.  */
+ 
+ static bool
+ gate_loop (function *fn)
+ {
+   if (!flag_tree_loop_optimize)
+     return false;
+ 
+   /* Make sure to drop / re-discover loops when necessary.  */
+   if (loops_state_satisfies_p (LOOPS_NEED_FIXUP))
+     fix_loop_structure (NULL);
+   return number_of_loops (fn) > 1;
+ }
+ 
  /* The loop superpass.  */
  
  namespace {
*************** public:
*** 68,74 ****
    {}
  
    /* opt_pass methods: */
!   virtual bool gate (function *) { return flag_tree_loop_optimize != 0; }
  
  }; // class pass_tree_loop
  
--- 84,90 ----
    {}
  
    /* opt_pass methods: */
!   virtual bool gate (function *fn) { return gate_loop (fn); }
  
  }; // class pass_tree_loop
  
*************** make_pass_tree_loop (gcc::context *ctxt)
*** 80,85 ****
--- 96,140 ----
    return new pass_tree_loop (ctxt);
  }
  
+ /* The no-loop superpass.  */
+ 
+ namespace {
+ 
+ const pass_data pass_data_tree_no_loop =
+ {
+   GIMPLE_PASS, /* type */
+   "no_loop", /* name */
+   OPTGROUP_NONE, /* optinfo_flags */
+   false, /* has_execute */
+   TV_TREE_NOLOOP, /* tv_id */
+   PROP_cfg, /* properties_required */
+   0, /* properties_provided */
+   0, /* properties_destroyed */
+   0, /* todo_flags_start */
+   0, /* todo_flags_finish */
+ };
+ 
+ class pass_tree_no_loop : public gimple_opt_pass
+ {
+ public:
+   pass_tree_no_loop (gcc::context *ctxt)
+     : gimple_opt_pass (pass_data_tree_no_loop, ctxt)
+   {}
+ 
+   /* opt_pass methods: */
+   virtual bool gate (function *fn) { return !gate_loop (fn); }
+ 
+ }; // class pass_tree_no_loop
+ 
+ } // anon namespace
+ 
+ gimple_opt_pass *
+ make_pass_tree_no_loop (gcc::context *ctxt)
+ {
+   return new pass_tree_no_loop (ctxt);
+ }
+ 
+ 
  /* Loop optimizer initialization.  */
  
  namespace {
Index: gcc/tree-vectorizer.c
===================================================================
*** gcc/tree-vectorizer.c.orig	2014-06-18 12:06:19.226205380 +0200
--- gcc/tree-vectorizer.c	2014-06-18 12:10:55.958186328 +0200
*************** along with GCC; see the file COPYING3.
*** 82,87 ****
--- 82,89 ----
  #include "tree-ssa-propagate.h"
  #include "dbgcnt.h"
  #include "gimple-fold.h"
+ #include "tree-scalar-evolution.h"
+ 
  
  /* Loop or bb location.  */
  source_location vect_location;
*************** public:
*** 610,615 ****
--- 612,618 ----
    {}
  
    /* opt_pass methods: */
+   opt_pass * clone () { return new pass_slp_vectorize (m_ctxt); }
    virtual bool gate (function *) { return flag_tree_slp_vectorize != 0; }
    virtual unsigned int execute (function *);
  
*************** pass_slp_vectorize::execute (function *f
*** 620,625 ****
--- 623,635 ----
  {
    basic_block bb;
  
+   bool in_loop_pipeline = scev_initialized_p ();
+   if (!in_loop_pipeline)
+     {
+       loop_optimizer_init (LOOPS_NORMAL);
+       scev_initialize ();
+     }
+ 
    init_stmt_vec_info_vec ();
  
    FOR_EACH_BB_FN (bb, fun)
*************** pass_slp_vectorize::execute (function *f
*** 639,644 ****
--- 649,661 ----
      }
  
    free_stmt_vec_info_vec ();
+ 
+   if (!in_loop_pipeline)
+     {
+       scev_finalize ();
+       loop_optimizer_finalize ();
+     }
+ 
    return 0;
  }
  
Index: gcc/timevar.def
===================================================================
*** gcc/timevar.def.orig	2014-06-18 12:06:18.615205422 +0200
--- gcc/timevar.def	2014-06-18 12:06:39.103204012 +0200
*************** DEFTIMEVAR (TV_TREE_CALL_CDCE	     , "tr
*** 162,167 ****
--- 162,168 ----
  DEFTIMEVAR (TV_TREE_DSE		     , "tree DSE")
  DEFTIMEVAR (TV_TREE_MERGE_PHI	     , "PHI merge")
  DEFTIMEVAR (TV_TREE_LOOP	     , "tree loop optimization")
+ DEFTIMEVAR (TV_TREE_NOLOOP           , "loopless fn")
  DEFTIMEVAR (TV_TREE_LOOP_BOUNDS	     , "tree loop bounds")
  DEFTIMEVAR (TV_LIM                   , "tree loop invariant motion")
  DEFTIMEVAR (TV_TREE_LOOP_IVCANON     , "tree canonical iv")
Index: gcc/tree-pass.h
===================================================================
*** gcc/tree-pass.h.orig	2014-06-18 12:06:18.615205422 +0200
--- gcc/tree-pass.h	2014-06-18 12:06:39.104204012 +0200
*************** extern gimple_opt_pass *make_pass_early_
*** 354,359 ****
--- 354,360 ----
  extern gimple_opt_pass *make_pass_tail_recursion (gcc::context *ctxt);
  extern gimple_opt_pass *make_pass_tail_calls (gcc::context *ctxt);
  extern gimple_opt_pass *make_pass_tree_loop (gcc::context *ctxt);
+ extern gimple_opt_pass *make_pass_tree_no_loop (gcc::context *ctxt);
  extern gimple_opt_pass *make_pass_tree_loop_init (gcc::context *ctxt);
  extern gimple_opt_pass *make_pass_lim (gcc::context *ctxt);
  extern gimple_opt_pass *make_pass_tree_unswitch (gcc::context *ctxt);
Index: gcc/passes.def
===================================================================
*** gcc/passes.def.orig	2014-06-18 12:06:18.615205422 +0200
--- gcc/passes.def	2014-06-18 12:06:39.104204012 +0200
*************** along with GCC; see the file COPYING3.
*** 201,206 ****
--- 201,208 ----
        NEXT_PASS (pass_sink_code);
        NEXT_PASS (pass_asan);
        NEXT_PASS (pass_tsan);
+       /* Pass group that runs when 1) enabled, 2) there are loops
+ 	 in the function.  */
        NEXT_PASS (pass_tree_loop);
        PUSH_INSERT_PASSES_WITHIN (pass_tree_loop)
  	  NEXT_PASS (pass_tree_loop_init);
*************** along with GCC; see the file COPYING3.
*** 233,242 ****
--- 235,252 ----
  	  NEXT_PASS (pass_complete_unroll);
  	  NEXT_PASS (pass_slp_vectorize);
  	  NEXT_PASS (pass_loop_prefetch);
+ 	  /* Run IVOPTs after the last pass that uses data-reference analysis
+ 	     as that doesn't handle TARGET_MEM_REFs.  */
  	  NEXT_PASS (pass_iv_optimize);
  	  NEXT_PASS (pass_lim);
  	  NEXT_PASS (pass_tree_loop_done);
        POP_INSERT_PASSES ()
+       /* Pass group that runs when pass_tree_loop is disabled or there
+          are no loops in the function.  */
+       NEXT_PASS (pass_tree_no_loop);
+       PUSH_INSERT_PASSES_WITHIN (pass_tree_no_loop)
+ 	  NEXT_PASS (pass_slp_vectorize);
+       POP_INSERT_PASSES ()
        NEXT_PASS (pass_lower_vector_ssa);
        NEXT_PASS (pass_cse_reciprocals);
        NEXT_PASS (pass_reassoc);

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-06-23 16:50 UTC | newest]

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2014-06-18 10:44 [PATCH][RFC] Gate loop passes group on number-of-loops > 1, add no-loops group Richard Biener
2014-06-18 10:54 ` Jakub Jelinek
2014-06-18 13:38 ` Jeff Law
2014-06-23 16:50   ` Richard Biener

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