CodeGen: Cast llvm.flt.rounds result to match __builtin_flt_rounds

llvm.flt.rounds returns an i32, but the builtin expects an integer. 
On targets where integers are not 32-bits clang tries to bitcast the result, causing an assertion failure.

The patch enables newlib build for msp430.

Patch by Edward Jones!

Differential Revision: https://reviews.llvm.org/D24461

llvm-svn: 351449
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 34bf194..6954d32 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -2130,6 +2130,17 @@
     return RValue::get(Builder.CreateZExt(V, ConvertType(E->getType())));
   }
 
+  case Builtin::BI__builtin_flt_rounds: {
+    Value *F = CGM.getIntrinsic(Intrinsic::flt_rounds);
+
+    llvm::Type *ResultType = ConvertType(E->getType());
+    Value *Result = Builder.CreateCall(F);
+    if (Result->getType() != ResultType)
+      Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/true,
+                                     "cast");
+    return RValue::get(Result);
+  }
+
   case Builtin::BI__builtin_fpclassify: {
     Value *V = EmitScalarExpr(E->getArg(5));
     llvm::Type *Ty = ConvertType(E->getArg(5)->getType());