Fix some -Wunreachable-code-aggressive warnings

Bug: chromium:1066980
Change-Id: I03a6b5253043bfb9825a1a64a1d9b060958e5a98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3094866
Auto-Submit: Nico Weber <thakis@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76293}

src/compiler/backend/arm64/code-generator-arm64.cc

@@ -235,7 +235,6 @@ class Arm64OperandConverter final : public InstructionOperandConverter {
             constant.ToDelayedStringConstant());
       case Constant::kRpoNumber:
         UNREACHABLE();  // TODO(dcarney): RPO immediates on arm64.
-        break;
     }
     UNREACHABLE();
   }
@@ -2633,7 +2632,6 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
           break;
         default:
           UNREACHABLE();
-          break;
       }
       break;
     }

src/compiler/backend/ia32/code-generator-ia32.cc

@@ -4013,7 +4013,6 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
     case kAtomicStoreWord16:
     case kAtomicStoreWord32:
       UNREACHABLE();  // Won't be generated by instruction selector.
-      break;
   }
   return kSuccess;
 }
@@ -4023,41 +4022,29 @@ static Condition FlagsConditionToCondition(FlagsCondition condition) {
     case kUnorderedEqual:
     case kEqual:
       return equal;
-      break;
     case kUnorderedNotEqual:
     case kNotEqual:
       return not_equal;
-      break;
     case kSignedLessThan:
       return less;
-      break;
     case kSignedGreaterThanOrEqual:
       return greater_equal;
-      break;
     case kSignedLessThanOrEqual:
       return less_equal;
-      break;
     case kSignedGreaterThan:
       return greater;
-      break;
     case kUnsignedLessThan:
       return below;
-      break;
     case kUnsignedGreaterThanOrEqual:
       return above_equal;
-      break;
     case kUnsignedLessThanOrEqual:
       return below_equal;
-      break;
     case kUnsignedGreaterThan:
       return above;
-      break;
     case kOverflow:
       return overflow;
-      break;
     case kNotOverflow:
       return no_overflow;
-      break;
     default:
       UNREACHABLE();
   }

src/diagnostics/ia32/disasm-ia32.cc

@@ -415,13 +415,11 @@ int DisassemblerIA32::PrintRightOperandHelper(
           UnimplementedInstruction();
           return 1;
         }
-      } else {
-        AppendToBuffer("[%s]", (this->*register_name)(rm));
-        return 1;
       }
-      break;
+      AppendToBuffer("[%s]", (this->*register_name)(rm));
+      return 1;
     case 1:  // fall through
-    case 2:
+    case 2: {
       if (rm == esp) {
         byte sib = *(modrmp + 1);
         int scale, index, base;
@@ -436,14 +434,13 @@ int DisassemblerIA32::PrintRightOperandHelper(
                          disp < 0 ? "-" : "+", disp < 0 ? -disp : disp);
         }
         return mod == 2 ? 6 : 3;
-      } else {
-        // No sib.
-        int disp = mod == 2 ? Imm32(modrmp + 1) : Imm8(modrmp + 1);
-        AppendToBuffer("[%s%s0x%x]", (this->*register_name)(rm),
-                       disp < 0 ? "-" : "+", disp < 0 ? -disp : disp);
-        return mod == 2 ? 5 : 2;
       }
-      break;
+      // No sib.
+      int disp = mod == 2 ? Imm32(modrmp + 1) : Imm8(modrmp + 1);
+      AppendToBuffer("[%s%s0x%x]", (this->*register_name)(rm),
+                     disp < 0 ? "-" : "+", disp < 0 ? -disp : disp);
+      return mod == 2 ? 5 : 2;
+    }
     case 3:
       AppendToBuffer("%s", (this->*register_name)(rm));
       return 1;

src/regexp/arm64/regexp-macro-assembler-arm64.cc

@@ -185,7 +185,6 @@ void RegExpMacroAssemblerARM64::AdvanceRegister(int reg, int by) {
       }
       default:
         UNREACHABLE();
-        break;
     }
   }
 }

test/cctest/test-assembler-arm64.cc

@@ -2168,7 +2168,6 @@ TEST(far_branch_backward) {
         break;
       default:
         UNREACHABLE();
-        break;
     }
 
     // Now go past the limit so that branches are now out of range.
@@ -2204,7 +2203,6 @@ TEST(far_branch_backward) {
         break;
       default:
         UNREACHABLE();
-        break;
     }
 
     __ Bind(&fail);

test/unittests/compiler/arm64/instruction-selector-arm64-unittest.cc

@@ -44,11 +44,9 @@ Node* BuildConstant(InstructionSelectorTest::StreamBuilder* m, MachineType type,
   switch (type.representation()) {
     case MachineRepresentation::kWord32:
       return m->Int32Constant(static_cast<int32_t>(value));
-      break;
 
     case MachineRepresentation::kWord64:
       return m->Int64Constant(value);
-      break;
 
     default:
       UNIMPLEMENTED();