VM: Enable branch merging of isnan, isinf.

runtime/vm/intermediate_language_mips.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/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
@@ skipping 3686 matching lines @@
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary = new(zone) LocationSummary(
       zone, kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresFpuRegister());
   summary->set_out(0, Location::RequiresRegister());
   return summary;
 }
 
 
+Condition DoubleTestOpInstr::EmitComparisonCode(FlowGraphCompiler* compiler,
+                                                BranchLabels labels) {
+  const DRegister value = locs()->in(0).fpu_reg();
+  const bool is_negated = kind() != Token::kEQ;
+  if (op_kind() == MethodRecognizer::kDouble_getIsNaN) {
+    __ cund(value, value);
+    if (labels.fall_through == labels.true_label) {
+      if (is_negated) {
+        __ bc1t(labels.false_label);
+      } else {
+        __ bc1f(labels.false_label);
+      }
+    } else if (labels.fall_through == labels.false_label) {
+      if (is_negated) {
+        __ bc1f(labels.true_label);
+      } else {
+        __ bc1t(labels.true_label);
+      }
+    } else {
+      if (is_negated) {
+        __ bc1t(labels.false_label);
+      } else {
+        __ bc1f(labels.false_label);
+      }
+      __ b(labels.true_label);
+    }
+    return Condition();  // Unused.
+  } else {
+    ASSERT(op_kind() == MethodRecognizer::kDouble_getIsInfinite);
+    __ mfc1(CMPRES1, EvenFRegisterOf(value));
+    // If the low word isn't zero, then it isn't infinity.
+    __ bne(CMPRES1, ZR, is_negated ? labels.true_label : labels.false_label);
+    __ mfc1(CMPRES1, OddFRegisterOf(value));
+    // Mask off the sign bit.
+    __ AndImmediate(CMPRES1, CMPRES1, 0x7FFFFFFF);
+    // Compare with +infinity.
+    __ LoadImmediate(CMPRES2, 0x7FF00000);
+    return Condition(CMPRES1, CMPRES2, is_negated ? NE : EQ);
+  }
+}
+
+void DoubleTestOpInstr::EmitBranchCode(FlowGraphCompiler* compiler,
+                                       BranchInstr* branch) {
+  ASSERT(compiler->is_optimizing());
+  BranchLabels labels = compiler->CreateBranchLabels(branch);
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  // Branches for isNaN are emitted in EmitComparisonCode already.
+  if (op_kind() == MethodRecognizer::kDouble_getIsInfinite) {
+    EmitBranchOnCondition(compiler, true_condition, labels);
+  }
+}
+
+
 void DoubleTestOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  ASSERT(compiler->is_optimizing());
-  const DRegister value = locs()->in(0).fpu_reg();
+  Label is_true, is_false;
+  BranchLabels labels = { &is_true, &is_false, &is_false };
+  Condition true_condition = EmitComparisonCode(compiler, labels);
+  // Branches for isNaN are emitted in EmitComparisonCode already.
+  if (op_kind() == MethodRecognizer::kDouble_getIsInfinite) {
+    EmitBranchOnCondition(compiler,  true_condition, labels);
+  }
   const Register result = locs()->out(0).reg();
-  if (op_kind() == MethodRecognizer::kDouble_getIsNaN) {
-    Label is_not_nan;
-    __ LoadObject(result, Bool::False());
-    __ cund(value, value);
-    __ bc1f(&is_not_nan);
-    __ LoadObject(result, Bool::True());
-    __ Bind(&is_not_nan);
-  } else {
-    ASSERT(op_kind() == MethodRecognizer::kDouble_getIsInfinite);
-    Label not_inf, done;
-    __ mfc1(TMP, EvenFRegisterOf(value));
-    __ mfc1(result, OddFRegisterOf(value));
-    // If the low word isn't zero, then it isn't infinity.
-    __ bne(TMP, ZR, &not_inf);
-    // Mask off the sign bit.
-    __ AndImmediate(result, result, 0x7FFFFFFF);
-    // Compare with +infinity.
-    __ BranchNotEqual(result, Immediate(0x7FF00000), &not_inf);
-
-    __ LoadObject(result, Bool::True());
-    __ b(&done);
-
-    __ Bind(&not_inf);
-    __ LoadObject(result, Bool::False());
-    __ Bind(&done);
-  }
+  Label done;
+  __ Comment("return bool");
+  __ Bind(&is_false);
+  __ LoadObject(result, Bool::False());
+  __ b(&done);
+  __ Bind(&is_true);
+  __ LoadObject(result, Bool::True());
+  __ Bind(&done);
 }
 
 
 LocationSummary* BinaryFloat32x4OpInstr::MakeLocationSummary(Zone* zone,
                                                              bool opt) const {
   UNIMPLEMENTED();
   return NULL;
 }
 
 
@@ skipping 2085 matching lines @@
                                 1,
                                 locs());
   __ lw(result, Address(SP, 1 * kWordSize));
   __ addiu(SP, SP, Immediate(2 * kWordSize));
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS