Recognize Math's min and max function for doubles and inline the operation.

runtime/vm/intermediate_language_arm.cc

Index: runtime/vm/intermediate_language_arm.cc
===================================================================
--- runtime/vm/intermediate_language_arm.cc	(revision 25251)
+++ runtime/vm/intermediate_language_arm.cc	(working copy)
@@ -3347,6 +3347,59 @@
 }
 
 
+LocationSummary* MathMinMaxInstr::MakeLocationSummary() const {
+  if (result_cid() == kDoubleCid) {
+    const intptr_t kNumInputs = 2;
+    const intptr_t kNumTemps = 1;
+    LocationSummary* summary =
+        new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
+    summary->set_in(0, Location::RequiresFpuRegister());
+    summary->set_in(1, Location::RequiresFpuRegister());
+    summary->set_temp(0, Location::RequiresRegister());
+    summary->set_out(Location::RequiresFpuRegister());
+    return summary;
+  }
+  ASSERT(result_cid() == kSmiCid);
+  UNIMPLEMENTED();
+  return NULL;
+}
+
+
+void MathMinMaxInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  if (result_cid() == kDoubleCid) {
+    Label done, is_left, is_nan;
+    DRegister left = EvenDRegisterOf(locs()->in(0).fpu_reg());
+    DRegister right = EvenDRegisterOf(locs()->in(1).fpu_reg());
+    DRegister result = EvenDRegisterOf(locs()->out().fpu_reg());
+    Register temp = locs()->temp(0).reg();
+    __ vcmpd(left, right);
+    __ vmstat();
+    __ b(&is_nan, VS);
+    Condition double_condition;
+    if (op_kind() == MethodRecognizer::kMathMin) {
+      double_condition = TokenKindToDoubleCondition(Token::kLT);
+    } else {
+      ASSERT(op_kind() == MethodRecognizer::kMathMax);
+      double_condition = TokenKindToDoubleCondition(Token::kGT);
+    }
+    __ b(&is_left, double_condition);
+    __ vmovd(result, right);
+    __ b(&done);
+    __ Bind(&is_left);
+    __ vmovd(result, left);

[regis, 2013/07/22 16:22:03]

You could make both vmovd instructions conditional and avoid the conditional
branches.

[srdjan, 2013/07/22 16:42:48]

Done.

+    __ b(&done);

[zra, 2013/07/22 16:21:02]

__ vmovd(result, left, double_condition);
__ vmovd(result, right, NegateCondition(double_condition));
__ b(&done);

[srdjan, 2013/07/22 16:42:48]

Done.

+    __ Bind(&is_nan);
+    static double kNaN = NAN;

[zra, 2013/07/22 16:21:02]

__ LoadDImmediate(result, NAN);

[srdjan, 2013/07/22 16:42:48]

Done.

+    __ LoadImmediate(temp, reinterpret_cast<int32_t>(&kNaN));
+    __ vldrd(result, Address(temp, 0));
+    __ Bind(&done);
+    return;
+  }
+  ASSERT(result_cid() == kSmiCid);
+  UNIMPLEMENTED();
+}
+
+
 LocationSummary* UnarySmiOpInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
@@ -3532,7 +3585,7 @@
 
 
 void InvokeMathCFunctionInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  // For pow-function return NAN if exponent is NAN.
+  // For pow-function return NaN if exponent is NaN.
   Label do_call, skip_call;
   if (recognized_kind() == MethodRecognizer::kDoublePow) {
     DRegister exp = EvenDRegisterOf(locs()->in(1).fpu_reg());