Cleanup of code generation for StrictCompare.

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/dart_entry.h"
@@ skipping 429 matching lines @@
     case LS: return CS;
     case HI: return CC;
     case CS: return LS;
     default:
       UNREACHABLE();
       return EQ;
   }
 }
 
 
-static void EmitBranchOnValue(FlowGraphCompiler* compiler,
-                              TargetEntryInstr* true_successor,
-                              TargetEntryInstr* false_successor,
-                              bool value) {
-  if (value && !compiler->CanFallThroughTo(true_successor)) {
-    __ b(compiler->GetJumpLabel(true_successor));
-  } else if (!value && !compiler->CanFallThroughTo(false_successor)) {
-    __ b(compiler->GetJumpLabel(false_successor));
-  }
-}
-
-
 static void EmitBranchOnCondition(FlowGraphCompiler* compiler,
                                   TargetEntryInstr* true_successor,
                                   TargetEntryInstr* false_successor,
                                   Condition true_condition) {
   if (compiler->CanFallThroughTo(false_successor)) {
     // If the next block is the false successor we will fall through to it.
     __ b(compiler->GetJumpLabel(true_successor), true_condition);
   } else {
     // If the next block is not the false successor we will branch to it.
     Condition false_condition = NegateCondition(true_condition);
@@ skipping 142 matching lines @@
     return;
   }
   UNREACHABLE();
 }
 
 
 void EqualityCompareInstr::EmitBranchCode(FlowGraphCompiler* compiler,
                                           BranchInstr* branch) {
   ASSERT((kind() == Token::kNE) || (kind() == Token::kEQ));
   if (operation_cid() == kSmiCid) {
-    // Deoptimizes if both arguments not Smi.
     EmitSmiComparisonOp(compiler, *locs(), kind(), branch);
     return;
   }
   if (operation_cid() == kMintCid) {
     EmitUnboxedMintEqualityOp(compiler, *locs(), kind(), branch);
     return;
   }
   if (operation_cid() == kDoubleCid) {
     EmitDoubleComparisonOp(compiler, *locs(), kind(), branch);
     return;
@@ skipping 3805 matching lines @@
     LocationSummary* locs =
         new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
     locs->set_in(0, Location::RegisterLocation(R0));
     locs->set_in(1, Location::RegisterLocation(R1));
     locs->set_out(Location::RegisterLocation(R0));
     return locs;
   }
   LocationSummary* locs =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   locs->set_in(0, Location::RegisterOrConstant(left()));
-  locs->set_in(1, Location::RegisterOrConstant(right()));
+  // 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(Location::RequiresRegister());
   return locs;
 }
 
 
 // Special code for numbers (compare values instead of references.)
 void StrictCompareInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
   Location left = locs()->in(0);
   Location right = locs()->in(1);
-  if (left.IsConstant() && right.IsConstant()) {
-    // TODO(vegorov): should be eliminated earlier by constant propagation.
-    const bool result = (kind() == Token::kEQ_STRICT) ?
-        left.constant().raw() == right.constant().raw() :
-        left.constant().raw() != right.constant().raw();
-    __ LoadObject(locs()->out().reg(), Bool::Get(result));
-    return;
-  }
+  ASSERT(!left.IsConstant() || !right.IsConstant());
   if (left.IsConstant()) {
     compiler->EmitEqualityRegConstCompare(right.reg(),
                                           left.constant(),
                                           needs_number_check(),
                                           token_pos());
   } else if (right.IsConstant()) {
     compiler->EmitEqualityRegConstCompare(left.reg(),
                                           right.constant(),
                                           needs_number_check(),
                                           token_pos());
   } else {
     compiler->EmitEqualityRegRegCompare(left.reg(),
                                        right.reg(),
                                        needs_number_check(),
                                        token_pos());
   }
 
   Register result = locs()->out().reg();
   Condition true_condition = (kind() == Token::kEQ_STRICT) ? EQ : NE;
   __ LoadObject(result, Bool::True(), true_condition);
   __ LoadObject(result, Bool::False(), NegateCondition(true_condition));
 }
 
 
 void StrictCompareInstr::EmitBranchCode(FlowGraphCompiler* compiler,
                                         BranchInstr* branch) {
   ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
   Location left = locs()->in(0);
   Location right = locs()->in(1);
-  if (left.IsConstant() && right.IsConstant()) {
-    // TODO(vegorov): should be eliminated earlier by constant propagation.
-    const bool result = (kind() == Token::kEQ_STRICT) ?
-        left.constant().raw() == right.constant().raw() :
-        left.constant().raw() != right.constant().raw();
-    EmitBranchOnValue(compiler,
-                      branch->true_successor(),
-                      branch->false_successor(),
-                      result);
-    return;
-  }
+  ASSERT(!left.IsConstant() || !right.IsConstant());
   if (left.IsConstant()) {
     compiler->EmitEqualityRegConstCompare(right.reg(),
                                           left.constant(),
                                           needs_number_check(),
                                           token_pos());
   } else if (right.IsConstant()) {
     compiler->EmitEqualityRegConstCompare(left.reg(),
                                           right.constant(),
                                           needs_number_check(),
                                           token_pos());
@@ skipping 85 matching lines @@
   compiler->GenerateCall(token_pos(),
                          &label,
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM