From 43e71f2ee933e25f5a1f45243af8be6c8290724c Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Sun, 21 Feb 2021 16:07:35 +0100
Subject: [PATCH] int cast

---
 compiler/builtins/src/std.rs     |  6 ++++++
 compiler/can/src/builtins.rs     |  7 +++++++
 compiler/gen/src/llvm/build.rs   | 10 ++++++++++
 compiler/module/src/low_level.rs |  1 +
 compiler/module/src/symbol.rs    |  2 ++
 compiler/mono/src/borrow.rs      |  2 +-
 6 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/compiler/builtins/src/std.rs b/compiler/builtins/src/std.rs
index 084edc1cd4..5a3b499dd7 100644
--- a/compiler/builtins/src/std.rs
+++ b/compiler/builtins/src/std.rs
@@ -360,6 +360,12 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         ),
     );
 
+    // intCast : Int a -> Int b
+    add_type(
+        Symbol::NUM_INT_CAST,
+        top_level_function(vec![int_type(flex(TVAR1))], Box::new(int_type(flex(TVAR2)))),
+    );
+
     // rem : Int a, Int a -> Result (Int a) [ DivByZero ]*
     add_type(
         Symbol::NUM_REM,
diff --git a/compiler/can/src/builtins.rs b/compiler/can/src/builtins.rs
index c8516d26ca..af38527fcc 100644
--- a/compiler/can/src/builtins.rs
+++ b/compiler/can/src/builtins.rs
@@ -156,6 +156,7 @@ pub fn builtin_defs_map(symbol: Symbol, var_store: &mut VarStore) -> Option<Def>
         NUM_SHIFT_LEFT=> num_shift_left_by,
         NUM_SHIFT_RIGHT => num_shift_right_by,
         NUM_SHIFT_RIGHT_ZERO_FILL => num_shift_right_zf_by,
+        NUM_INT_CAST=> num_int_cast,
         RESULT_MAP => result_map,
         RESULT_MAP_ERR => result_map_err,
         RESULT_WITH_DEFAULT => result_with_default,
@@ -285,6 +286,7 @@ pub fn builtin_defs(var_store: &mut VarStore) -> MutMap<Symbol, Def> {
         Symbol::NUM_SHIFT_LEFT => num_shift_left_by,
         Symbol::NUM_SHIFT_RIGHT => num_shift_right_by,
         Symbol::NUM_SHIFT_RIGHT_ZERO_FILL => num_shift_right_zf_by,
+        Symbol::NUM_INT_CAST=> num_int_cast,
         Symbol::RESULT_MAP => result_map,
         Symbol::RESULT_MAP_ERR => result_map_err,
         Symbol::RESULT_WITH_DEFAULT => result_with_default,
@@ -1331,6 +1333,11 @@ fn num_shift_right_zf_by(symbol: Symbol, var_store: &mut VarStore) -> Def {
     lowlevel_2(symbol, LowLevel::NumShiftRightZfBy, var_store)
 }
 
+/// Num.intCast: Int a -> Int b
+fn num_int_cast(symbol: Symbol, var_store: &mut VarStore) -> Def {
+    lowlevel_1(symbol, LowLevel::NumIntCast, var_store)
+}
+
 /// List.isEmpty : List * -> Bool
 fn list_is_empty(symbol: Symbol, var_store: &mut VarStore) -> Def {
     let list_var = var_store.fresh();
diff --git a/compiler/gen/src/llvm/build.rs b/compiler/gen/src/llvm/build.rs
index ed149b77a4..9ba362841f 100644
--- a/compiler/gen/src/llvm/build.rs
+++ b/compiler/gen/src/llvm/build.rs
@@ -3983,6 +3983,16 @@ fn run_low_level<'a, 'ctx, 'env>(
                 op,
             )
         }
+        NumIntCast => {
+            debug_assert_eq!(args.len(), 1);
+
+            let arg = load_symbol(scope, &args[0]).into_int_value();
+
+            let to = basic_type_from_layout(env.arena, env.context, layout, env.ptr_bytes)
+                .into_int_type();
+
+            env.builder.build_int_cast(arg, to, "inc_cast").into()
+        }
         Eq => {
             debug_assert_eq!(args.len(), 2);
 
diff --git a/compiler/module/src/low_level.rs b/compiler/module/src/low_level.rs
index 7279a4ae76..640b8c8bca 100644
--- a/compiler/module/src/low_level.rs
+++ b/compiler/module/src/low_level.rs
@@ -83,6 +83,7 @@ pub enum LowLevel {
     NumShiftLeftBy,
     NumShiftRightBy,
     NumShiftRightZfBy,
+    NumIntCast,
     Eq,
     NotEq,
     And,
diff --git a/compiler/module/src/symbol.rs b/compiler/module/src/symbol.rs
index a7d19116dc..62f5a9d457 100644
--- a/compiler/module/src/symbol.rs
+++ b/compiler/module/src/symbol.rs
@@ -854,6 +854,8 @@ define_builtins! {
         93 NUM_AT_NATURAL: "@Natural"
         94 NUM_NATURAL: "Natural" imported
         95 NUM_NAT: "Nat" imported
+        96 NUM_INT_CAST: "intCast"
+
     }
     2 BOOL: "Bool" => {
         0 BOOL_BOOL: "Bool" imported // the Bool.Bool type alias
diff --git a/compiler/mono/src/borrow.rs b/compiler/mono/src/borrow.rs
index 294e2582c0..c0d4f1e091 100644
--- a/compiler/mono/src/borrow.rs
+++ b/compiler/mono/src/borrow.rs
@@ -671,7 +671,7 @@ pub fn lowlevel_borrow_signature(arena: &Bump, op: LowLevel) -> &[bool] {
         }
 
         NumAbs | NumNeg | NumSin | NumCos | NumSqrtUnchecked | NumRound | NumCeiling | NumFloor
-        | NumToFloat | Not | NumIsFinite | NumAtan | NumAcos | NumAsin => {
+        | NumToFloat | Not | NumIsFinite | NumAtan | NumAcos | NumAsin | NumIntCast => {
             arena.alloc_slice_copy(&[irrelevant])
         }
         StrStartsWith | StrEndsWith => arena.alloc_slice_copy(&[owned, borrowed]),