[crankshaft][arm][mips] Fix Math.min(0, 0)

src/crankshaft/arm/lithium-codegen-arm.cc

 // Copyright 2012 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/crankshaft/arm/lithium-codegen-arm.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/crankshaft/arm/lithium-gap-resolver-arm.h"
@@ skipping 1914 matching lines @@
     // Left equals right => check for -0.
     __ VFPCompareAndSetFlags(left_reg, 0.0);
     if (left_reg.is(result_reg) || right_reg.is(result_reg)) {
       __ b(ne, &done);  // left == right != 0.
     } else {
       __ b(ne, &return_left);  // left == right != 0.
     }
     // At this point, both left and right are either 0 or -0.
     if (operation == HMathMinMax::kMathMin) {
       // We could use a single 'vorr' instruction here if we had NEON support.
+      // The algorithm is: -((-L) + (-R)), which in case of L and R being
+      // different registers is most efficiently expressed as -((-L) - R).
       __ vneg(left_reg, left_reg);
-      __ vsub(result_reg, left_reg, right_reg);
+      if (left_reg.is(right_reg)) {
+        __ vadd(result_reg, left_reg, right_reg);
+      } else {
+        __ vsub(result_reg, left_reg, right_reg);
+      }
       __ vneg(result_reg, result_reg);
     } else {
       // Since we operate on +0 and/or -0, vadd and vand have the same effect;
       // the decision for vadd is easy because vand is a NEON instruction.
       __ vadd(result_reg, left_reg, right_reg);
     }
     __ b(&done);
 
     __ bind(&result_is_nan);
     __ vadd(result_reg, left_reg, right_reg);
@@ skipping 3604 matching lines @@
   __ push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8