Refactor compute minus zero checks into a proper HPhase.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 22 matching lines @@
 #include "codegen.h"
 #include "full-codegen.h"
 #include "hashmap.h"
 #include "hydrogen-bce.h"
 #include "hydrogen-dce.h"
 #include "hydrogen-environment-liveness.h"
 #include "hydrogen-escape-analysis.h"
 #include "hydrogen-infer-representation.h"
 #include "hydrogen-infer-types.h"
 #include "hydrogen-gvn.h"
+#include "hydrogen-minus-zero.h"
 #include "hydrogen-osr.h"
 #include "hydrogen-range-analysis.h"
 #include "hydrogen-redundant-phi.h"
 #include "hydrogen-representation-changes.h"
 #include "hydrogen-sce.h"
 #include "hydrogen-uint32-analysis.h"
 #include "lithium-allocator.h"
 #include "parser.h"
 #include "scopeinfo.h"
 #include "scopes.h"
@@ skipping 2574 matching lines @@
 
     if (!mergelist.is_empty()) {
       // Merge the accumulated simulates at the end of the block.
       HSimulate* last = mergelist.RemoveLast();
       last->MergeWith(&mergelist);
     }
   }
 }
 
 
-void HGraph::PropagateMinusZeroChecks(HValue* value, BitVector* visited) {
-  HValue* current = value;
-  while (current != NULL) {
-    if (visited->Contains(current->id())) return;
-
-    // For phis, we must propagate the check to all of its inputs.
-    if (current->IsPhi()) {
-      visited->Add(current->id());
-      HPhi* phi = HPhi::cast(current);
-      for (int i = 0; i < phi->OperandCount(); ++i) {
-        PropagateMinusZeroChecks(phi->OperandAt(i), visited);
-      }
-      break;
-    }
-
-    // For multiplication, division, and Math.min/max(), we must propagate
-    // to the left and the right side.
-    if (current->IsMul()) {
-      HMul* mul = HMul::cast(current);
-      mul->EnsureAndPropagateNotMinusZero(visited);
-      PropagateMinusZeroChecks(mul->left(), visited);
-      PropagateMinusZeroChecks(mul->right(), visited);
-    } else if (current->IsDiv()) {
-      HDiv* div = HDiv::cast(current);
-      div->EnsureAndPropagateNotMinusZero(visited);
-      PropagateMinusZeroChecks(div->left(), visited);
-      PropagateMinusZeroChecks(div->right(), visited);
-    } else if (current->IsMathMinMax()) {
-      HMathMinMax* minmax = HMathMinMax::cast(current);
-      visited->Add(minmax->id());
-      PropagateMinusZeroChecks(minmax->left(), visited);
-      PropagateMinusZeroChecks(minmax->right(), visited);
-    }
-
-    current = current->EnsureAndPropagateNotMinusZero(visited);
-  }
-}
-
-
 void HGraph::RecursivelyMarkPhiDeoptimizeOnUndefined(HPhi* phi) {
   if (!phi->CheckFlag(HValue::kAllowUndefinedAsNaN)) return;
   phi->ClearFlag(HValue::kAllowUndefinedAsNaN);
   for (int i = 0; i < phi->OperandCount(); ++i) {
     HValue* input = phi->OperandAt(i);
     if (input->IsPhi()) {
       RecursivelyMarkPhiDeoptimizeOnUndefined(HPhi::cast(input));
     }
   }
 }
@@ skipping 12 matching lines @@
       HValue* use_value = it.value();
       if (!use_value->CheckFlag(HValue::kAllowUndefinedAsNaN)) {
         RecursivelyMarkPhiDeoptimizeOnUndefined(phi);
         break;
       }
     }
   }
 }
 
 
-void HGraph::ComputeMinusZeroChecks() {
-  HPhase phase("H_Compute minus zero checks", this);
-  BitVector visited(GetMaximumValueID(), zone());
-  for (int i = 0; i < blocks_.length(); ++i) {
-    for (HInstructionIterator it(blocks_[i]); !it.Done(); it.Advance()) {
-      HInstruction* current = it.Current();
-      if (current->IsChange()) {
-        HChange* change = HChange::cast(current);
-        // Propagate flags for negative zero checks upwards from conversions
-        // int32-to-tagged and int32-to-double.
-        Representation from = change->value()->representation();
-        ASSERT(from.Equals(change->from()));
-        if (from.IsInteger32()) {
-          ASSERT(change->to().IsTagged() ||
-                 change->to().IsDouble() ||
-                 change->to().IsSmi());
-          ASSERT(visited.IsEmpty());
-          PropagateMinusZeroChecks(change->value(), &visited);
-          visited.Clear();
-        }
-      }
-    }
-  }
-}
-
-
 // Implementation of utility class to encapsulate the translation state for
 // a (possibly inlined) function.
 FunctionState::FunctionState(HOptimizedGraphBuilder* owner,
                              CompilationInfo* info,
                              InliningKind inlining_kind)
     : owner_(owner),
       compilation_info_(info),
       call_context_(NULL),
       inlining_kind_(inlining_kind),
       function_return_(NULL),
@@ skipping 470 matching lines @@
   if (FLAG_opt_safe_uint32_operations) Run<HUint32AnalysisPhase>();
 
   if (FLAG_use_canonicalizing) Canonicalize();
 
   if (FLAG_use_escape_analysis) Run<HEscapeAnalysisPhase>();
 
   if (FLAG_use_gvn) Run<HGlobalValueNumberingPhase>();
 
   if (FLAG_use_range) Run<HRangeAnalysisPhase>();
 
-  ComputeMinusZeroChecks();
+  Run<HComputeMinusZeroChecksPhase>();
 
   // Eliminate redundant stack checks on backwards branches.
   Run<HStackCheckEliminationPhase>();
 
   if (FLAG_idefs) SetupInformativeDefinitions();
   if (FLAG_array_bounds_checks_elimination && !FLAG_idefs) {
     Run<HBoundsCheckEliminationPhase>();
   }
   if (FLAG_array_index_dehoisting) DehoistSimpleArrayIndexComputations();
   if (FLAG_dead_code_elimination) Run<HDeadCodeEliminationPhase>();
@@ skipping 7005 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal