Switch Num.tan to a zig builtin

It should be able to share some work between sine and cosine to run faster.

crates/compiler/builtins/bitcode/src/main.zig

@@ -163,6 +163,7 @@ comptime {
 
         num.exportSin(T, ROC_BUILTINS ++ "." ++ NUM ++ ".sin.");
         num.exportCos(T, ROC_BUILTINS ++ "." ++ NUM ++ ".cos.");
+        num.exportTan(T, ROC_BUILTINS ++ "." ++ NUM ++ ".tan.");
 
         num.exportPow(T, ROC_BUILTINS ++ "." ++ NUM ++ ".pow.");
         num.exportLog(T, ROC_BUILTINS ++ "." ++ NUM ++ ".log.");

crates/compiler/builtins/bitcode/src/num.zig

@@ -168,6 +168,15 @@ pub fn exportCos(comptime T: type, comptime name: []const u8) void {
     @export(f, .{ .name = name ++ @typeName(T), .linkage = .Strong });
 }
 
+pub fn exportTan(comptime T: type, comptime name: []const u8) void {
+    comptime var f = struct {
+        fn func(input: T) callconv(.C) T {
+            return math.tan(input);
+        }
+    }.func;
+    @export(f, .{ .name = name ++ @typeName(T), .linkage = .Strong });
+}
+
 pub fn exportLog(comptime T: type, comptime name: []const u8) void {
     comptime var f = struct {
         fn func(input: T) callconv(.C) T {

crates/compiler/builtins/roc/Num.roc

@@ -825,11 +825,7 @@ max = \a, b ->
 
 sin : Frac a -> Frac a
 cos : Frac a -> Frac a
-
 tan : Frac a -> Frac a
-tan = \x ->
-    # `tan` is not available as an intrinsic in LLVM
-    Num.div (Num.sin x) (Num.cos x)
 
 asin : Frac a -> Frac a
 acos : Frac a -> Frac a

crates/compiler/builtins/src/bitcode.rs

@@ -272,6 +272,7 @@ macro_rules! int_intrinsic {
 
 pub const NUM_SIN: IntrinsicName = float_intrinsic!("roc_builtins.num.sin");
 pub const NUM_COS: IntrinsicName = float_intrinsic!("roc_builtins.num.cos");
+pub const NUM_TAN: IntrinsicName = float_intrinsic!("roc_builtins.num.tan");
 pub const NUM_ASIN: IntrinsicName = float_intrinsic!("roc_builtins.num.asin");
 pub const NUM_ACOS: IntrinsicName = float_intrinsic!("roc_builtins.num.acos");
 pub const NUM_ATAN: IntrinsicName = float_intrinsic!("roc_builtins.num.atan");

crates/compiler/can/src/builtins.rs

@@ -186,6 +186,7 @@ map_symbol_to_lowlevel_and_arity! {
     NumNeg; NUM_NEG; 1,
     NumSin; NUM_SIN; 1,
     NumCos; NUM_COS; 1,
+    NumTan; NUM_TAN; 1,
     NumSqrtUnchecked; NUM_SQRT; 1,
     NumLogUnchecked; NUM_LOG; 1,
     NumRound; NUM_ROUND; 1,

crates/compiler/gen_llvm/src/llvm/lowlevel.rs

@@ -935,6 +935,7 @@ pub(crate) fn run_low_level<'a, 'ctx>(
         | NumLogUnchecked
         | NumSin
         | NumCos
+        | NumTan
         | NumCeiling
         | NumFloor
         | NumToFrac
@@ -2655,6 +2656,7 @@ fn build_float_unary_op<'a, 'ctx>(
         // trigonometry
         NumSin => call_bitcode_fn(env, &[arg.into()], &bitcode::NUM_SIN[float_width]),
         NumCos => call_bitcode_fn(env, &[arg.into()], &bitcode::NUM_COS[float_width]),
+        NumTan => call_bitcode_fn(env, &[arg.into()], &bitcode::NUM_TAN[float_width]),
 
         NumAtan => call_bitcode_fn(env, &[arg.into()], &bitcode::NUM_ATAN[float_width]),
         NumAcos => call_bitcode_fn(env, &[arg.into()], &bitcode::NUM_ACOS[float_width]),

crates/compiler/gen_wasm/src/low_level.rs

@@ -1539,6 +1539,12 @@ impl<'a> LowLevelCall<'a> {
                 }
                 _ => panic_ret_type(),
             },
+            NumTan => match self.ret_layout_raw {
+                LayoutRepr::Builtin(Builtin::Float(width)) => {
+                    self.load_args_and_call_zig(backend, &bitcode::NUM_TAN[width]);
+                }
+                _ => panic_ret_type(),
+            },
             NumSqrtUnchecked => {
                 self.load_args(backend);
                 match self.ret_layout_raw {

crates/compiler/module/src/low_level.rs

@@ -78,6 +78,7 @@ pub enum LowLevel {
     NumNeg,
     NumSin,
     NumCos,
+    NumTan,
     NumSqrtUnchecked,
     NumLogUnchecked,
     NumRound,
@@ -324,6 +325,7 @@ map_symbol_to_lowlevel! {
     NumNeg <= NUM_NEG,
     NumSin <= NUM_SIN,
     NumCos <= NUM_COS,
+    NumTan <= NUM_TAN,
     NumSqrtUnchecked <= NUM_SQRT,
     NumLogUnchecked <= NUM_LOG,
     NumRound <= NUM_ROUND,

crates/compiler/mono/src/drop_specialization.rs

@@ -1571,6 +1571,7 @@ fn low_level_no_rc(lowlevel: &LowLevel) -> RC {
         | NumNeg
         | NumSin
         | NumCos
+        | NumTan
         | NumSqrtUnchecked
         | NumLogUnchecked
         | NumRound

crates/compiler/mono/src/inc_dec.rs

@@ -1327,6 +1327,7 @@ fn lowlevel_borrow_signature(arena: &Bump, op: LowLevel) -> &[Ownership] {
         | NumNeg
         | NumSin
         | NumCos
+        | NumTan
         | NumSqrtUnchecked
         | NumLogUnchecked
         | NumRound

crates/compiler/mono/src/low_level.rs

@@ -101,6 +101,7 @@ enum FirstOrder {
     NumNeg,
     NumSin,
     NumCos,
+    NumTan,
     NumSqrtUnchecked,
     NumLogUnchecked,
     NumRound,