MIPS: Do not use the 64-bit floor and truncate instructions in fp32 mode.

src/compiler/mips/instruction-selector-mips.cc

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index 04b33ceceac820b77d10e5c3d470703b8402122e..5f64dbd16188b406d6e40c6960b56ccede1a2c67 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -980,7 +980,8 @@ InstructionSelector::SupportedMachineOperatorFlags() {
   MachineOperatorBuilder::Flags flags =
       MachineOperatorBuilder::kFloat32Abs | MachineOperatorBuilder::kFloat64Abs;
 
-  if (IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) {
+  if ((IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) &&
+      IsFp64Mode()) {
     flags |= MachineOperatorBuilder::kFloat64RoundDown |
              MachineOperatorBuilder::kFloat64RoundTruncate;
   }