Expose SIMD.Float32x4 type to Javascript.

src/mips64/lithium-codegen-mips64.cc

Index: src/mips64/lithium-codegen-mips64.cc
diff --git a/src/mips64/lithium-codegen-mips64.cc b/src/mips64/lithium-codegen-mips64.cc
index 5ae92b0439533f29cfe03db257a816c6036a5fa1..ae0ed0ae67c2536e04419861f9fbb7f4d1b5a1b3 100644
--- a/src/mips64/lithium-codegen-mips64.cc
+++ b/src/mips64/lithium-codegen-mips64.cc
@@ -2281,6 +2281,14 @@ void LCodeGen::DoBranch(LBranch* instr) {
         __ Branch(instr->TrueLabel(chunk_), eq, scratch, Operand(SYMBOL_TYPE));
       }
 
+      if (expected.Contains(ToBooleanStub::SIMD_VALUE)) {
+        // Symbol value -> true.
+        const Register scratch = scratch1();
+        __ lbu(scratch, FieldMemOperand(map, Map::kInstanceTypeOffset));
+        __ Branch(instr->TrueLabel(chunk_), eq, scratch,
+                  Operand(FLOAT32X4_TYPE));
+      }
+
       if (expected.Contains(ToBooleanStub::HEAP_NUMBER)) {
         // heap number -> false iff +0, -0, or NaN.
         DoubleRegister dbl_scratch = double_scratch0();