[turbofan] Avoid some redundant checks of unordered comparison on arm/arm64.

src/compiler/arm/code-generator-arm.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/arm/macro-assembler-arm.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 675 matching lines @@
   Label* tlabel = branch->true_label;
   Label* flabel = branch->false_label;
   switch (branch->condition) {
     case kUnorderedEqual:
       __ b(vs, flabel);
     // Fall through.
     case kEqual:
       __ b(eq, tlabel);
       break;
     case kUnorderedNotEqual:
-      __ b(vs, tlabel);
-    // Fall through.
+      // Unordered or not equal can be tested with "ne" condtion.
+      // See ARMv7 manual A8.3 - Conditional execution.
     case kNotEqual:
       __ b(ne, tlabel);
       break;
     case kSignedLessThan:
       __ b(lt, tlabel);
       break;
     case kSignedGreaterThanOrEqual:
       __ b(ge, tlabel);
       break;
     case kSignedLessThanOrEqual:
       __ b(le, tlabel);
       break;
     case kSignedGreaterThan:
       __ b(gt, tlabel);
       break;
     case kUnorderedLessThan:
       __ b(vs, flabel);
     // Fall through.
     case kUnsignedLessThan:
       __ b(lo, tlabel);
       break;
     case kUnorderedGreaterThanOrEqual:
-      __ b(vs, tlabel);
-    // Fall through.
+      // Unordered, greater than or equal can be tested with "hs" condtion.
+      // See ARMv7 manual A8.3 - Conditional execution.
     case kUnsignedGreaterThanOrEqual:
       __ b(hs, tlabel);
       break;
     case kUnorderedLessThanOrEqual:
       __ b(vs, flabel);
     // Fall through.
     case kUnsignedLessThanOrEqual:
       __ b(ls, tlabel);
       break;
     case kUnorderedGreaterThan:
-      __ b(vs, tlabel);
-    // Fall through.
+      // Unordered or greater than can be tested with "hi" condtion.
+      // See ARMv7 manual A8.3 - Conditional execution.
     case kUnsignedGreaterThan:
       __ b(hi, tlabel);
       break;
     case kOverflow:
       __ b(vs, tlabel);
       break;
     case kNotOverflow:
       __ b(vc, tlabel);
       break;
   }
@@ skipping 358 matching lines @@
     }
   }
   MarkLazyDeoptSite();
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8