MIPS: Skip some conditional deopts for Div/Mul when all uses are truncating.

src/mips/lithium-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1228 matching lines @@
   }
 
   // Check for (kMinInt / -1).
   if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
     Label left_not_min_int;
     __ Branch(&left_not_min_int, ne, left, Operand(kMinInt));
     DeoptimizeIf(eq, instr->environment(), right, Operand(-1));
     __ bind(&left_not_min_int);
   }
 
-  __ mfhi(result);
-  DeoptimizeIf(ne, instr->environment(), result, Operand(zero_reg));
+  if (!instr->hydrogen()->CheckFlag(HInstruction::kAllUsesTruncatingToInt32)) {
+    __ mfhi(result);
+    DeoptimizeIf(ne, instr->environment(), result, Operand(zero_reg));
+  }
   __ mflo(result);
 }
 
 
 void LCodeGen::DoMultiplyAddD(LMultiplyAddD* instr) {
   DoubleRegister addend = ToDoubleRegister(instr->addend());
   DoubleRegister multiplier = ToDoubleRegister(instr->multiplier());
   DoubleRegister multiplicand = ToDoubleRegister(instr->multiplicand());
 
   // This is computed in-place.
@@ skipping 4450 matching lines @@
   __ Subu(scratch, result, scratch);
   __ lw(result, FieldMemOperand(scratch,
                                 FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal