rustc_trans: promote constant rvalues in functions as an optimization.

Author: eddyb

src/librustc_llvm/lib.rs

@@ -893,6 +893,7 @@ extern {
 
 
     /* Operations on global variables */
+    pub fn LLVMIsAGlobalVariable(GlobalVar: ValueRef) -> ValueRef;
     pub fn LLVMAddGlobal(M: ModuleRef, Ty: TypeRef, Name: *const c_char)
                          -> ValueRef;
     pub fn LLVMAddGlobalInAddressSpace(M: ModuleRef,

src/librustc_trans/trans/_match.rs

@@ -274,14 +274,14 @@ impl<'a, 'tcx> Opt<'a, 'tcx> {
         match *self {
             ConstantValue(ConstantExpr(lit_expr)) => {
                 let lit_ty = ty::node_id_to_type(bcx.tcx(), lit_expr.id);
-                let (llval, _) = consts::const_expr(ccx, &*lit_expr);
+                let (llval, _) = consts::const_expr(ccx, &*lit_expr, bcx.fcx.param_substs);
                 let lit_datum = immediate_rvalue(llval, lit_ty);
                 let lit_datum = unpack_datum!(bcx, lit_datum.to_appropriate_datum(bcx));
                 SingleResult(Result::new(bcx, lit_datum.val))
             }
             ConstantRange(ConstantExpr(ref l1), ConstantExpr(ref l2)) => {
-                let (l1, _) = consts::const_expr(ccx, &**l1);
-                let (l2, _) = consts::const_expr(ccx, &**l2);
+                let (l1, _) = consts::const_expr(ccx, &**l1, bcx.fcx.param_substs);
+                let (l2, _) = consts::const_expr(ccx, &**l2, bcx.fcx.param_substs);
                 RangeResult(Result::new(bcx, l1), Result::new(bcx, l2))
             }
             Variant(disr_val, ref repr, _) => {
@@ -795,8 +795,8 @@ fn compare_values<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
 
     let _icx = push_ctxt("compare_values");
     if ty::type_is_scalar(rhs_t) {
-        let rs = compare_scalar_types(cx, lhs, rhs, rhs_t, ast::BiEq);
-        return Result::new(rs.bcx, rs.val);
+        let cmp = compare_scalar_types(cx, lhs, rhs, rhs_t, ast::BiEq);
+        return Result::new(cx, cmp);
     }
 
     match rhs_t.sty {
@@ -1122,18 +1122,15 @@ fn compile_submatch_continue<'a, 'p, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
                             }
                             RangeResult(Result { val: vbegin, .. },
                                         Result { bcx, val: vend }) => {
-                                let Result { bcx, val: llge } =
-                                    compare_scalar_types(
-                                    bcx, test_val,
-                                    vbegin, t, ast::BiGe);
-                                let Result { bcx, val: llle } =
-                                    compare_scalar_types(
-                                    bcx, test_val, vend,
-                                    t, ast::BiLe);
+                                let llge = compare_scalar_types(bcx, test_val, vbegin,
+                                                                t, ast::BiGe);
+                                let llle = compare_scalar_types(bcx, test_val, vend,
+                                                                t, ast::BiLe);
                                 Result::new(bcx, And(bcx, llge, llle, DebugLoc::None))
                             }
                             LowerBound(Result { bcx, val }) => {
-                                compare_scalar_types(bcx, test_val, val, t, ast::BiGe)
+                                Result::new(bcx, compare_scalar_types(bcx, test_val, val,
+                                                                      t, ast::BiGe))
                             }
                         }
                     };