ARM: for StrictCompare cache constant values in register instead of materializing it each time. Nex…

runtime/vm/intermediate_language_arm.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_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/cpu.h"
@@ skipping 275 matching lines @@
   if (!locs()->out(0).IsInvalid()) {
     const Register result = locs()->out(0).reg();
     __ LoadObject(result, value());
   }
 }
 
 
 LocationSummary* UnboxedConstantInstr::MakeLocationSummary(Isolate* isolate,
                                                            bool opt) const {
   const intptr_t kNumInputs = 0;
-  const intptr_t kNumTemps = 1;
+  const intptr_t kNumTemps = (representation_ == kUnboxedInt32) ? 0 : 1;
   LocationSummary* locs = new(isolate) LocationSummary(
       isolate, kNumInputs, kNumTemps, LocationSummary::kNoCall);
   locs->set_out(0, Location::RequiresFpuRegister());
-  locs->set_temp(0, Location::RequiresRegister());
+  if (representation_ != kUnboxedInt32) {
+    locs->set_temp(0, Location::RequiresRegister());
+  }
   return locs;
 }
 
 
 void UnboxedConstantInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   // The register allocator drops constant definitions that have no uses.
   if (!locs()->out(0).IsInvalid()) {
     switch (representation_) {
       case kUnboxedDouble:
         if (Utils::DoublesBitEqual(Double::Cast(value()).value(), 0.0) &&
@@ skipping 6797 matching lines @@
   if (needs_number_check()) {
     LocationSummary* locs = new(isolate) LocationSummary(
         isolate, kNumInputs, kNumTemps, LocationSummary::kCall);
     locs->set_in(0, Location::RegisterLocation(R0));
     locs->set_in(1, Location::RegisterLocation(R1));
     locs->set_out(0, Location::RegisterLocation(R0));
     return locs;
   }
   LocationSummary* locs = new(isolate) LocationSummary(
       isolate, kNumInputs, kNumTemps, LocationSummary::kNoCall);
-  locs->set_in(0, Location::RegisterOrConstant(left()));
-  // Only one of the inputs can be a constant. Choose register if the first one
-  // is a constant.
-  locs->set_in(1, locs->in(0).IsConstant()
-                      ? Location::RequiresRegister()
-                      : Location::RegisterOrConstant(right()));
+
+  // If a constant has more than one use, make sure it is loaded in register
+  // so that multiple immediate loads can be avoided.
+  ConstantInstr* constant = left()->definition()->AsConstant();
+  if ((constant != NULL) && !left()->IsSingleUse()) {
+    locs->set_in(0, Location::RequiresRegister());
+  } else {
+    locs->set_in(0, Location::RegisterOrConstant(left()));
+  }
+
+  constant = right()->definition()->AsConstant();
+  if ((constant != NULL) && !right()->IsSingleUse()) {
+    locs->set_in(1, Location::RequiresRegister());
+  } else {
+    // Only one of the inputs can be a constant. Choose register if the first
+    // one is a constant.
+    locs->set_in(1, locs->in(0).IsConstant()
+        ? Location::RequiresRegister()
+        : Location::RegisterOrConstant(right()));
+  }
   locs->set_out(0, Location::RequiresRegister());
   return locs;
 }
 
 
 Condition StrictCompareInstr::EmitComparisonCode(FlowGraphCompiler* compiler,
                                                  BranchLabels labels) {
   Location left = locs()->in(0);
   Location right = locs()->in(1);
   ASSERT(!left.IsConstant() || !right.IsConstant());
@@ skipping 87 matching lines @@
   compiler->GenerateCall(token_pos(), &label, stub_kind_, locs());
 #if defined(DEBUG)
   __ LoadImmediate(R4, kInvalidObjectPointer);
   __ LoadImmediate(R5, kInvalidObjectPointer);
 #endif
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM