Index: src/compiler/ia32/instruction-selector-ia32.cc |
diff --git a/src/compiler/ia32/instruction-selector-ia32.cc b/src/compiler/ia32/instruction-selector-ia32.cc |
index da2a6594196951d33fd196a3070bda2b7958695f..beec701903ec4598f26fb3d093b7898b2ea27804 100644 |
--- a/src/compiler/ia32/instruction-selector-ia32.cc |
+++ b/src/compiler/ia32/instruction-selector-ia32.cc |
@@ -928,6 +928,67 @@ void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch, |
} |
+void InstructionSelector::VisitSwitch(Node* node, BasicBlock* default_branch, |
+ BasicBlock** case_branches, |
+ int32_t* case_values, size_t case_count, |
+ int32_t min_value, int32_t max_value) { |
+ IA32OperandGenerator g(this); |
+ InstructionOperand value_operand = g.UseRegister(node->InputAt(0)); |
+ InstructionOperand default_operand = g.Label(default_branch); |
+ |
+ // Note that {value_range} can be 0 if {min_value} is -2^31 and {max_value} |
+ // is 2^31-1, so don't assume that it's non-zero below. |
+ size_t value_range = |
+ 1u + bit_cast<uint32_t>(max_value) - bit_cast<uint32_t>(min_value); |
+ |
+ // Determine whether to issue an ArchTableSwitch or an ArchLookupSwitch |
+ // instruction. |
+ size_t table_space_cost = 4 + value_range; |
+ size_t table_time_cost = 3; |
+ size_t lookup_space_cost = 3 + 2 * case_count; |
+ size_t lookup_time_cost = case_count; |
+ if (case_count > 4 && |
+ table_space_cost + 3 * table_time_cost <= |
+ lookup_space_cost + 3 * lookup_time_cost && |
+ min_value > std::numeric_limits<int32_t>::min()) { |
+ InstructionOperand index_operand = value_operand; |
+ if (min_value) { |
+ index_operand = g.TempRegister(); |
+ Emit(kIA32Lea | AddressingModeField::encode(kMode_MRI), index_operand, |
+ value_operand, g.TempImmediate(-min_value)); |
+ } |
+ size_t input_count = 2 + value_range; |
+ auto* inputs = zone()->NewArray<InstructionOperand>(input_count); |
+ inputs[0] = index_operand; |
+ std::fill(&inputs[1], &inputs[input_count], default_operand); |
+ for (size_t index = 0; index < case_count; ++index) { |
+ size_t value = case_values[index] - min_value; |
+ BasicBlock* branch = case_branches[index]; |
+ DCHECK_LE(0u, value); |
+ DCHECK_LT(value + 2, input_count); |
+ inputs[value + 2] = g.Label(branch); |
+ } |
+ Emit(kArchTableSwitch, 0, nullptr, input_count, inputs, 0, nullptr) |
+ ->MarkAsControl(); |
+ return; |
+ } |
+ |
+ // Generate a sequence of conditional jumps. |
+ size_t input_count = 2 + case_count * 2; |
+ auto* inputs = zone()->NewArray<InstructionOperand>(input_count); |
+ inputs[0] = value_operand; |
+ inputs[1] = default_operand; |
+ for (size_t index = 0; index < case_count; ++index) { |
+ int32_t value = case_values[index]; |
+ BasicBlock* branch = case_branches[index]; |
+ inputs[index * 2 + 2 + 0] = g.TempImmediate(value); |
+ inputs[index * 2 + 2 + 1] = g.Label(branch); |
+ } |
+ Emit(kArchLookupSwitch, 0, nullptr, input_count, inputs, 0, nullptr) |
+ ->MarkAsControl(); |
+} |
+ |
+ |
void InstructionSelector::VisitWord32Equal(Node* const node) { |
FlagsContinuation cont(kEqual, node); |
Int32BinopMatcher m(node); |