MIPS: [turbofan] Use RINT instruction for Float64|32Round ops. on r6.

src/mips/constants-mips.h

Index: src/mips/constants-mips.h
diff --git a/src/mips/constants-mips.h b/src/mips/constants-mips.h
index 4eaf7937727b307e9ed7fc790aef5ec198523000..bea688ff1ad0fb031e7229db8f3988e79854e5c2 100644
--- a/src/mips/constants-mips.h
+++ b/src/mips/constants-mips.h
@@ -777,7 +777,12 @@ enum FPURoundingMode {
   kRoundToNearest = RN,
   kRoundToZero = RZ,
   kRoundToPlusInf = RP,
-  kRoundToMinusInf = RM
+  kRoundToMinusInf = RM,
+
+  mode_round = RN,

[paul.l..., 2015/12/10 05:39:49]

nit: suggest kMode_round, etc. A little closer to naming convention, but still
lets you stringify the opcode.

+  mode_ceil = RP,
+  mode_floor = RM,
+  mode_trunc = RZ
 };
 
 const uint32_t kFPURoundingModeMask = 3 << 0;