Enable correct optimized double modulo operation. (TODO: enable remainder optimization).

runtime/vm/intermediate_language_x64.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_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 2403 matching lines @@
   }
 }
 
 
 LocationSummary* InvokeMathCFunctionInstr::MakeLocationSummary() const {
   // Calling convention on x64 uses XMM0 and XMM1 to pass the first two
   // double arguments and XMM0 to return the result. Unfortunately
   // currently we can't specify these registers because ParallelMoveResolver
   // assumes that XMM0 is free at all times.
   // TODO(vegorov): allow XMM0 to be used.
+  if (recognized_kind() == MethodRecognizer::kDoubleMod) {
+    ASSERT(InputCount() == 2);
+    const intptr_t kNumTemps = 2;
+    LocationSummary* result =
+        new LocationSummary(InputCount(), kNumTemps, LocationSummary::kCall);
+    result->set_in(0, Location::FpuRegisterLocation(XMM1, Location::kDouble));
+    result->set_in(1, Location::FpuRegisterLocation(XMM2, Location::kDouble));
+    result->set_out(Location::FpuRegisterLocation(XMM1, Location::kDouble));
+    result->set_temp(0, Location::FpuRegisterLocation(XMM2, Location::kDouble));
+    result->set_temp(1, Location::FpuRegisterLocation(XMM3, Location::kDouble));
+    return result;
+  }
   ASSERT((InputCount() == 1) || (InputCount() == 2));
   const intptr_t kNumTemps = 0;
   LocationSummary* result =
       new LocationSummary(InputCount(), kNumTemps, LocationSummary::kCall);
   result->set_in(0, Location::FpuRegisterLocation(XMM1, Location::kDouble));
   if (InputCount() == 2) {
     result->set_in(1, Location::FpuRegisterLocation(XMM2, Location::kDouble));
   }
   result->set_out(Location::FpuRegisterLocation(XMM1, Location::kDouble));
   return result;
 }
 
 
 void InvokeMathCFunctionInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  if (recognized_kind() == MethodRecognizer::kDoubleMod) {
+    // Preserve right argument.
+    __ pushq(RAX);
+    __ movsd(Address(RSP, 0), locs()->in(1).fpu_reg());
+  }
+
   ASSERT(locs()->in(0).fpu_reg() == XMM1);
   __ EnterFrame(0);
   __ ReserveAlignedFrameSpace(0);
   __ movaps(XMM0, locs()->in(0).fpu_reg());
   if (InputCount() == 2) {
     ASSERT(locs()->in(1).fpu_reg() == XMM2);
     __ movaps(XMM1, locs()->in(1).fpu_reg());
   }
   __ CallRuntime(TargetFunction());
   __ movaps(locs()->out().fpu_reg(), XMM0);
   __ leave();
+
+  if (recognized_kind() == MethodRecognizer::kDoubleMod) {
+    // Result of C call is remainder, convert it to modulo.
+    Label done, equal_zero, right_greater_equal_zero;
+    XmmRegister remainder = locs()->out().fpu_reg();
+    XmmRegister zero_temp = locs()->temp(0).fpu_reg();
+    XmmRegister right_temp = locs()->temp(1).fpu_reg();
+
+    __ xorpd(zero_temp, zero_temp);  // 0.0 -> 'temp'.
+    __ comisd(remainder, zero_temp);
+    __ j(PARITY_EVEN, &done, Assembler::kNearJump);  // NaN -> false;
+    __ j(EQUAL, &equal_zero, Assembler::kNearJump);
+    __ j(ABOVE, &done, Assembler::kNearJump);  // (remainder) > 0 -> done.
+    // remainder < 0.
+    // Load preserved right argument.
+    __ movsd(right_temp, Address(RSP, 0));
+    __ comisd(right_temp, zero_temp);
+    __ j(ABOVE_EQUAL, &right_greater_equal_zero, Assembler::kNearJump);
+    // right < 0.
+    __ subsd(remainder, right_temp);
+    __ jmp(&done, Assembler::kNearJump);
+
+    __ Bind(&right_greater_equal_zero);
+    __ addsd(remainder, right_temp);
+    __ jmp(&done);
+
+    __ Bind(&equal_zero);
+    // Switch to the positive 0.0 (just in case it was negative).
+    __ movsd(remainder, zero_temp);
+
+    __ Bind(&done);
+    __ Drop(1);  // Remove preserved right argument.
+  }
 }
 
 
 LocationSummary* PolymorphicInstanceCallInstr::MakeLocationSummary() const {
   return MakeCallSummary();
 }
 
 
 void PolymorphicInstanceCallInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Label* deopt = compiler->AddDeoptStub(instance_call()->deopt_id(),
@@ skipping 535 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64