VM: Support phis with pair representations.

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2013, 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/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/compiler.h"
 #include "vm/cpu.h"
@@ skipping 608 matching lines @@
     current_iterator_ = NULL;
   }
 }
 
 
 static void EnsureSSATempIndex(FlowGraph* graph,
                                Definition* defn,
                                Definition* replacement) {
   if ((replacement->ssa_temp_index() == -1) &&
       (defn->ssa_temp_index() != -1)) {
-    replacement->set_ssa_temp_index(graph->alloc_ssa_temp_index());
+    graph->AllocateSSAIndexes(replacement);
   }
 }
 
 
 static void ReplaceCurrentInstruction(ForwardInstructionIterator* iterator,
                                       Instruction* current,
                                       Instruction* replacement,
                                       FlowGraph* graph) {
   Definition* current_defn = current->AsDefinition();
   if ((replacement != NULL) && (current_defn != NULL)) {
@@ skipping 191 matching lines @@
     case kFloat64x2Cid:
       if (ShouldInlineSimd()) {
         unboxed = kUnboxedFloat64x2;
       }
       break;
   }
 
   if ((kSmiBits < 32) &&
       (unboxed == kTagged) &&
       phi->Type()->IsInt() &&
-      RangeUtils::Fits(phi->range(), RangeBoundary::kRangeBoundaryInt32)) {
+      RangeUtils::Fits(phi->range(), RangeBoundary::kRangeBoundaryInt64)) {
     // On 32-bit platforms conservatively unbox phis that:
     //   - are proven to be of type Int;
     //   - fit into 32bits range;

[regis, 2015/10/06 17:37:24]

update comment?

[Florian Schneider, 2015/10/07 09:44:11]

Done.

[regis, 2015/10/07 17:23:38]

Did not upload updated comment?

[Florian Schneider, 2015/10/08 09:39:26]

Forgot at first. Added it in patchset #8.

     //   - have either constants or Box() operations as inputs;
     //   - have at least one Box() operation as an input;
     //   - are used in at least 1 Unbox() operation.
     bool should_unbox = false;
     for (intptr_t i = 0; i < phi->InputCount(); i++) {
       Definition* input = phi->InputAt(i)->definition();
       if (input->IsBox() &&
           RangeUtils::Fits(input->range(),
-                           RangeBoundary::kRangeBoundaryInt32)) {
+                           RangeBoundary::kRangeBoundaryInt64)) {
         should_unbox = true;
       } else if (!input->IsConstant()) {
         should_unbox = false;
         break;
       }
     }
 
     if (should_unbox) {
       // We checked inputs. Check if phi is used in at least one unbox
       // operation.
@@ skipping 11 matching lines @@
           break;
         }
       }
 
       if (!has_unboxed_use) {
         should_unbox = false;
       }
     }
 
     if (should_unbox) {
-      unboxed = kUnboxedInt32;
+      unboxed =
+          RangeUtils::Fits(phi->range(), RangeBoundary::kRangeBoundaryInt32)
+          ? kUnboxedInt32 : kUnboxedMint;
     }
   }
 
   phi->set_representation(unboxed);
 }
 
 
 void FlowGraphOptimizer::SelectRepresentations() {
   // Conservatively unbox all phis that were proven to be of Double,
   // Float32x4, or Int32x4 type.
@@ skipping 6170 matching lines @@
       // they might contain values that were replaced and removed
       // from the graph by this iteration.
       // To prevent using them we additionally mark definitions themselves
       // as replaced and store a pointer to the replacement.
       Definition* replacement = (*pred_out_values)[place_id]->Replacement();
       Value* input = new(Z) Value(replacement);
       phi->SetInputAt(i, input);
       replacement->AddInputUse(input);
     }
 
-    phi->set_ssa_temp_index(graph_->alloc_ssa_temp_index());
+    graph_->AllocateSSAIndexes(phi);
     phis_.Add(phi);  // Postpone phi insertion until after load forwarding.
 
     if (FLAG_trace_load_optimization) {
       THR_Print("created pending phi %s for %s at B%" Pd "\n",
                 phi->ToCString(),
                 aliased_set_->places()[place_id]->ToCString(),
                 block->block_id());
     }
   }
 
@@ skipping 1703 matching lines @@
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits_collector_.exits().length(); i++) {
     CreateMaterializationAt(
         exits_collector_.exits()[i], alloc, *slots);
   }
 }
 
 
 }  // namespace dart