MIPS: Optimise Math.floor(x/y) to use integer division for MIPS.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 8a6ccbc9e2cbe364fb7e973372e478437c45a73d..78212655b7744a7fb65ae8ffae20f9715fb5d02c 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1533,8 +1533,6 @@ HValue* HUnaryMathOperation::Canonicalize() {
     // with its input.
     if (val->representation().IsInteger32()) return val;
 
-#if defined(V8_TARGET_ARCH_ARM) || defined(V8_TARGET_ARCH_IA32) || \
-        defined(V8_TARGET_ARCH_X64)
     if (val->IsDiv() && (val->UseCount() == 1)) {
       HDiv* hdiv = HDiv::cast(val);
       HValue* left = hdiv->left();
@@ -1550,6 +1548,9 @@ HValue* HUnaryMathOperation::Canonicalize() {
       HValue* new_right =
           LChunkBuilder::SimplifiedDivisorForMathFloorOfDiv(right);
       if (new_right == NULL &&
+#ifdef V8_TARGET_ARCH_MIPS
+          false &&  // MathFloorOfDiv on MIPS can only operate on HConstant
+#endif
 #ifdef V8_TARGET_ARCH_ARM
           CpuFeatures::IsSupported(SUDIV) &&
 #endif
@@ -1585,7 +1586,6 @@ HValue* HUnaryMathOperation::Canonicalize() {
       // Return NULL to remove this instruction from the graph.
       return NULL;
     }
-#endif  // V8_TARGET_ARCH_ARM
   }
   return this;
 }