Revert "Reduce copying, redundancy & repetition for codegen of comparison instructions"

runtime/vm/intermediate_language_arm64.cc

Index: runtime/vm/intermediate_language_arm64.cc
diff --git a/runtime/vm/intermediate_language_arm64.cc b/runtime/vm/intermediate_language_arm64.cc
index c5eb0dd20cf62ed5296012d9e73d39021f64568f..8986f04fcbcb965addd2e62b72ad06e02645bfa6 100644
--- a/runtime/vm/intermediate_language_arm64.cc
+++ b/runtime/vm/intermediate_language_arm64.cc
@@ -165,11 +165,8 @@ void IfThenElseInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   ASSERT(!left.IsConstant() || !right.IsConstant());
 
   // Emit comparison code. This must not overwrite the result register.
-  // IfThenElseInstr::Supports() should prevent EmitComparisonCode from using
-  // the labels or returning an invalid condition.
   BranchLabels labels = {NULL, NULL, NULL};
   Condition true_condition = comparison()->EmitComparisonCode(compiler, labels);
-  ASSERT(true_condition != kInvalidCondition);
 
   const bool is_power_of_two_kind = IsPowerOfTwoKind(if_true_, if_false_);
 
@@ -543,17 +540,11 @@ static Condition TokenKindToDoubleCondition(Token::Kind kind) {
 
 static Condition EmitDoubleComparisonOp(FlowGraphCompiler* compiler,
                                         LocationSummary* locs,
-                                        BranchLabels labels,
                                         Token::Kind kind) {
   const VRegister left = locs->in(0).fpu_reg();
   const VRegister right = locs->in(1).fpu_reg();
   __ fcmpd(left, right);
   Condition true_condition = TokenKindToDoubleCondition(kind);
-  if (true_condition != NE) {
-    // Special case for NaN comparison. Result is always false unless
-    // relational operator is !=.
-    __ b(labels.false_label, VS);
-  }
   return true_condition;
 }
 
@@ -564,8 +555,47 @@ Condition EqualityCompareInstr::EmitComparisonCode(FlowGraphCompiler* compiler,
     return EmitSmiComparisonOp(compiler, locs(), kind());
   } else {
     ASSERT(operation_cid() == kDoubleCid);
-    return EmitDoubleComparisonOp(compiler, locs(), labels, kind());
+    return EmitDoubleComparisonOp(compiler, locs(), kind());
+  }
+}
+
+
+void EqualityCompareInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  ASSERT((kind() == Token::kEQ) || (kind() == Token::kNE));
+  Label is_true, is_false;
+  BranchLabels labels = {&is_true, &is_false, &is_false};
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  if ((operation_cid() == kDoubleCid) && (true_condition != NE)) {
+    // Special case for NaN comparison. Result is always false unless
+    // relational operator is !=.
+    __ b(&is_false, VS);
   }
+  EmitBranchOnCondition(compiler, true_condition, labels);
+  // TODO(zra): instead of branching, use the csel instruction to get
+  // True or False into result.
+  const Register result = locs()->out(0).reg();
+  Label done;
+  __ Bind(&is_false);
+  __ LoadObject(result, Bool::False());
+  __ b(&done);
+  __ Bind(&is_true);
+  __ LoadObject(result, Bool::True());
+  __ Bind(&done);
+}
+
+
+void EqualityCompareInstr::EmitBranchCode(FlowGraphCompiler* compiler,
+                                          BranchInstr* branch) {
+  ASSERT((kind() == Token::kNE) || (kind() == Token::kEQ));
+
+  BranchLabels labels = compiler->CreateBranchLabels(branch);
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  if ((operation_cid() == kDoubleCid) && (true_condition != NE)) {
+    // Special case for NaN comparison. Result is always false unless
+    // relational operator is !=.
+    __ b(labels.false_label, VS);
+  }
+  EmitBranchOnCondition(compiler, true_condition, labels);
 }
 
 
@@ -598,6 +628,20 @@ Condition TestSmiInstr::EmitComparisonCode(FlowGraphCompiler* compiler,
 }
 
 
+void TestSmiInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  // Never emitted outside of the BranchInstr.
+  UNREACHABLE();
+}
+
+
+void TestSmiInstr::EmitBranchCode(FlowGraphCompiler* compiler,
+                                  BranchInstr* branch) {
+  BranchLabels labels = compiler->CreateBranchLabels(branch);
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  EmitBranchOnCondition(compiler, true_condition, labels);
+}
+
+
 LocationSummary* TestCidsInstr::MakeLocationSummary(Zone* zone,
                                                     bool opt) const {
   const intptr_t kNumInputs = 1;
@@ -650,9 +694,32 @@ Condition TestCidsInstr::EmitComparisonCode(FlowGraphCompiler* compiler,
   } else {
     __ b(deopt);
   }
-  // Dummy result as this method already did the jump, there's no need
-  // for the caller to branch on a condition.
-  return kInvalidCondition;
+  // Dummy result as the last instruction is a jump, any conditional
+  // branch using the result will therefore be skipped.
+  return EQ;
+}
+
+
+void TestCidsInstr::EmitBranchCode(FlowGraphCompiler* compiler,
+                                   BranchInstr* branch) {
+  BranchLabels labels = compiler->CreateBranchLabels(branch);
+  EmitComparisonCode(compiler, labels);
+}
+
+
+void TestCidsInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  const Register result_reg = locs()->out(0).reg();
+  Label is_true, is_false, done;
+  BranchLabels labels = {&is_true, &is_false, &is_false};
+  EmitComparisonCode(compiler, labels);
+  // TODO(zra): instead of branching, use the csel instruction to get
+  // True or False into result.
+  __ Bind(&is_false);
+  __ LoadObject(result_reg, Bool::False());
+  __ b(&done);
+  __ Bind(&is_true);
+  __ LoadObject(result_reg, Bool::True());
+  __ Bind(&done);
 }
 
 
@@ -688,8 +755,44 @@ Condition RelationalOpInstr::EmitComparisonCode(FlowGraphCompiler* compiler,
     return EmitSmiComparisonOp(compiler, locs(), kind());
   } else {
     ASSERT(operation_cid() == kDoubleCid);
-    return EmitDoubleComparisonOp(compiler, locs(), labels, kind());
+    return EmitDoubleComparisonOp(compiler, locs(), kind());
+  }
+}
+
+
+void RelationalOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  Label is_true, is_false;
+  BranchLabels labels = {&is_true, &is_false, &is_false};
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  if ((operation_cid() == kDoubleCid) && (true_condition != NE)) {
+    // Special case for NaN comparison. Result is always false unless
+    // relational operator is !=.
+    __ b(&is_false, VS);
+  }
+  EmitBranchOnCondition(compiler, true_condition, labels);
+  // TODO(zra): instead of branching, use the csel instruction to get
+  // True or False into result.
+  const Register result = locs()->out(0).reg();
+  Label done;
+  __ Bind(&is_false);
+  __ LoadObject(result, Bool::False());
+  __ b(&done);
+  __ Bind(&is_true);
+  __ LoadObject(result, Bool::True());
+  __ Bind(&done);
+}
+
+
+void RelationalOpInstr::EmitBranchCode(FlowGraphCompiler* compiler,
+                                       BranchInstr* branch) {
+  BranchLabels labels = compiler->CreateBranchLabels(branch);
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  if ((operation_cid() == kDoubleCid) && (true_condition != NE)) {
+    // Special case for NaN comparison. Result is always false unless
+    // relational operator is !=.
+    __ b(labels.false_label, VS);
   }
+  EmitBranchOnCondition(compiler, true_condition, labels);
 }
 
 
@@ -3014,7 +3117,6 @@ void CheckedSmiComparisonInstr::EmitBranchCode(FlowGraphCompiler* compiler,
   compiler->AddSlowPathCode(slow_path);
   EMIT_SMI_CHECK;
   Condition true_condition = EmitComparisonCode(compiler, labels);
-  ASSERT(true_condition != kInvalidCondition);
   EmitBranchOnCondition(compiler, true_condition, labels);
   __ Bind(slow_path->exit_label());
 }
@@ -3029,7 +3131,6 @@ void CheckedSmiComparisonInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   compiler->AddSlowPathCode(slow_path);
   EMIT_SMI_CHECK;
   Condition true_condition = EmitComparisonCode(compiler, labels);
-  ASSERT(true_condition != kInvalidCondition);
   EmitBranchOnCondition(compiler, true_condition, labels);
   Register result = locs()->out(0).reg();
   __ Bind(&false_label);
@@ -3658,6 +3759,33 @@ Condition DoubleTestOpInstr::EmitComparisonCode(FlowGraphCompiler* compiler,
 }
 
 
+void DoubleTestOpInstr::EmitBranchCode(FlowGraphCompiler* compiler,
+                                       BranchInstr* branch) {
+  ASSERT(compiler->is_optimizing());
+  BranchLabels labels = compiler->CreateBranchLabels(branch);
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  EmitBranchOnCondition(compiler, true_condition, labels);
+}
+
+
+void DoubleTestOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  ASSERT(compiler->is_optimizing());
+  Label is_true, is_false;
+  BranchLabels labels = {&is_true, &is_false, &is_false};
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  const Register result = locs()->out(0).reg();
+  if (op_kind() == MethodRecognizer::kDouble_getIsNaN) {
+    __ LoadObject(result, Bool::False());
+    __ LoadObject(TMP, Bool::True());
+    __ csel(result, TMP, result, true_condition);
+  } else {
+    __ LoadObject(result, Bool::False());
+    __ LoadObject(TMP, Bool::True());
+    __ csel(result, TMP, result, true_condition);
+  }
+}
+
+
 LocationSummary* BinaryFloat32x4OpInstr::MakeLocationSummary(Zone* zone,
                                                              bool opt) const {
   const intptr_t kNumInputs = 2;
@@ -5861,16 +5989,16 @@ Condition StrictCompareInstr::EmitComparisonCode(FlowGraphCompiler* compiler,
 }
 
 
-void ComparisonInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+void StrictCompareInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  __ Comment("StrictCompareInstr");
+  ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
+
   Label is_true, is_false;
   BranchLabels labels = {&is_true, &is_false, &is_false};
   Condition true_condition = EmitComparisonCode(compiler, labels);
-  const Register result = this->locs()->out(0).reg();
+  EmitBranchOnCondition(compiler, true_condition, labels);
 
-  // TODO(dartbug.com/29908): Use csel here for better branch prediction?
-  if (true_condition != kInvalidCondition) {
-    EmitBranchOnCondition(compiler, true_condition, labels);
-  }
+  const Register result = locs()->out(0).reg();
   Label done;
   __ Bind(&is_false);
   __ LoadObject(result, Bool::False());
@@ -5881,13 +6009,13 @@ void ComparisonInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 }
 
 
-void ComparisonInstr::EmitBranchCode(FlowGraphCompiler* compiler,
-                                     BranchInstr* branch) {
+void StrictCompareInstr::EmitBranchCode(FlowGraphCompiler* compiler,
+                                        BranchInstr* branch) {
+  ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
+
   BranchLabels labels = compiler->CreateBranchLabels(branch);
   Condition true_condition = EmitComparisonCode(compiler, labels);
-  if (true_condition != kInvalidCondition) {
-    EmitBranchOnCondition(compiler, true_condition, labels);
-  }
+  EmitBranchOnCondition(compiler, true_condition, labels);
 }