[turbofan] Implemented the optional Float32RoundTruncate operator.

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index 1b129707c10cd6890ffa5fb7998ca1e70dad0b9e..fa276668ae41399a2bf0a65460c6c6084b2eee45 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -931,6 +931,8 @@ void InstructionSelector::VisitNode(Node* node) {
       return MarkAsFloat32(node), VisitFloat32RoundUp(node);
     case IrOpcode::kFloat64RoundUp:
       return MarkAsFloat64(node), VisitFloat64RoundUp(node);
+    case IrOpcode::kFloat32RoundTruncate:
+      return MarkAsFloat32(node), VisitFloat32RoundTruncate(node);
     case IrOpcode::kFloat64RoundTruncate:
       return MarkAsFloat64(node), VisitFloat64RoundTruncate(node);
     case IrOpcode::kFloat64RoundTiesAway: