Merge sin(a), cos(a) into one instruction. TODO: Implement for ARM and MIPS.

runtime/vm/compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 340 matching lines @@
                          isolate);
 
         FlowGraphOptimizer optimizer(flow_graph);
         optimizer.ApplyICData();
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         // Optimize (a << b) & c patterns, merge operations. Must occur before
         // 'SelectRepresentations' which inserts conversion nodes.
         // TODO(srdjan): Moved before inlining until environment use list can
         // be used to detect when shift-left is outside the scope of bit-and.
         optimizer.TryOptimizePatterns();

[Florian Schneider, 2013/12/03 14:12:04]

Is it necessary to run this twice, here and below? Also, I'm not sure that the
TODO above is still applicable: We do track environment uses properly now,
right?

[srdjan, 2013/12/03 18:10:01]

The one below, after CSE is important. I will eliminate the one here. Adding
comment:
Run after CSE in order to have more opportunity to merge instructions that have
same inputs.

[srdjan, 2013/12/03 21:01:39]

Correction: the early one is needed to mark left shifts as truncating. Left it
here,

On 2013/12/03 18:10:01, srdjan wrote:

         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         // Inlining (mutates the flow graph)
         if (FLAG_use_inlining) {
           TimerScope timer(FLAG_compiler_stats,
                            &CompilerStats::graphinliner_timer);
           // Propagate types to create more inlining opportunities.
           FlowGraphTypePropagator::Propagate(flow_graph);
           DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
@@ skipping 61 matching lines @@
         if (FLAG_common_subexpression_elimination) {
           if (DominatorBasedCSE::Optimize(flow_graph)) {
             DEBUG_ASSERT(flow_graph->VerifyUseLists());
             // Do another round of CSE to take secondary effects into account:
             // e.g. when eliminating dependent loads (a.x[0] + a.x[0])
             // TODO(fschneider): Change to a one-pass optimization pass.
             DominatorBasedCSE::Optimize(flow_graph);
             DEBUG_ASSERT(flow_graph->VerifyUseLists());
           }
         }
+        optimizer.TryOptimizePatterns();
+        DEBUG_ASSERT(flow_graph->VerifyUseLists());
+
         if (FLAG_loop_invariant_code_motion &&
             (function.deoptimization_counter() <
              FLAG_deoptimization_counter_licm_threshold)) {
           LICM licm(flow_graph);
           licm.Optimize();
           DEBUG_ASSERT(flow_graph->VerifyUseLists());
         }
         flow_graph->RemoveRedefinitions();
 
         if (FLAG_range_analysis) {
@@ skipping 499 matching lines @@
       Object::Handle(isolate->object_store()->sticky_error());
     isolate->object_store()->clear_sticky_error();
     isolate->set_long_jump_base(base);
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart