Handle non-power-of-2 divisors in division-like operations

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 63cf9c5bcc10c4a8371d84d616daafb5f5e3c070..c72f0db2f2b08639905b2453934608ba75637dbf 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -1363,6 +1363,10 @@ class MacroAssembler: public Assembler {
                                   Register filler);
 
 
+  // Emit code for a flooring division by a constant. The dividend register is
+  // unchanged, the result is in rdx, and rax gets clobbered.
+  void FlooringDiv(Register dividend, int32_t divisor);
+
   // ---------------------------------------------------------------------------
   // StatsCounter support