Make float -> int casts actually work

Author: arielb1

src/librustc_trans/trans/consts.rs

@@ -660,9 +660,11 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
               (CastTy::Float, CastTy::Float) => {
                 llvm::LLVMConstFPCast(v, llty.to_ref())
               }
+              (CastTy::Float, CastTy::Int(IntTy::I)) => {
+                llvm::LLVMConstFPToSI(v, llty.to_ref())
+              }
               (CastTy::Float, CastTy::Int(_)) => {
-                if ty::type_is_signed(t_expr) { llvm::LLVMConstFPToSI(v, llty.to_ref()) }
-                else { llvm::LLVMConstFPToUI(v, llty.to_ref()) }
+                llvm::LLVMConstFPToUI(v, llty.to_ref())
               }
               (CastTy::Ptr(_), CastTy::Ptr(_)) | (CastTy::FnPtr, CastTy::Ptr(_))
                     | (CastTy::RPtr(_), CastTy::Ptr(_)) => {

src/test/run-pass/cast-rfc0401.rs

@@ -75,7 +75,6 @@ fn main()
     assert_eq!(9.223372036854775e18f64 as i64, 0x7ffffffffffffc00i64);
     assert_eq!(-9.223372036854776e18f64 as i64, 0x8000000000000000u64 as i64);
 
-
     // addr-ptr-cast/ptr-addr-cast (thin ptr)
     let p: *const [u8; 1] = lsz as *const [u8; 1];
     assert_eq!(p as usize, lsz);