Merge pull request #21257 from mlugg/computed-goto-3

compiler: implement labeled switch/continue

4 files changed, 231 insertions, 0 deletions

diff --git a/test/behavior.zig b/test/behavior.zig
index eca6cee5af..f0d05a146a 100644
--- a/test/behavior.zig
+++ b/test/behavior.zig
@@ -89,6 +89,7 @@ test {
     _ = @import("behavior/struct_contains_null_ptr_itself.zig");
     _ = @import("behavior/struct_contains_slice_of_itself.zig");
     _ = @import("behavior/switch.zig");
+    _ = @import("behavior/switch_loop.zig");
     _ = @import("behavior/switch_prong_err_enum.zig");
     _ = @import("behavior/switch_prong_implicit_cast.zig");
     _ = @import("behavior/switch_on_captured_error.zig");
diff --git a/test/behavior/switch.zig b/test/behavior/switch.zig
index 1cec0dfad4..f1ded573a0 100644
--- a/test/behavior/switch.zig
+++ b/test/behavior/switch.zig
@@ -961,3 +961,27 @@ test "block error return trace index is reset between prongs" {
     };
     try result;
 }
+
+test "labeled switch with break" {
+    var six: u32 = undefined;
+    six = 6;
+
+    const val = s: switch (six) {
+        0...4 => break :s false,
+        5 => break :s false,
+        6...7 => break :s true,
+        else => break :s false,
+    };
+
+    try expect(val);
+
+    // Make sure the switch is implicitly comptime!
+    const comptime_val = s: switch (@as(u32, 6)) {
+        0...4 => break :s false,
+        5 => break :s false,
+        6...7 => break :s true,
+        else => break :s false,
+    };
+
+    comptime assert(comptime_val);
+}
diff --git a/test/behavior/switch_loop.zig b/test/behavior/switch_loop.zig
new file mode 100644
index 0000000000..d35a4e1636
--- /dev/null
+++ b/test/behavior/switch_loop.zig
@@ -0,0 +1,200 @@
+const builtin = @import("builtin");
+const std = @import("std");
+const expect = std.testing.expect;
+
+test "simple switch loop" {
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // TODO
+
+    const S = struct {
+        fn doTheTest() !void {
+            var start: u32 = undefined;
+            start = 32;
+            const result: u32 = s: switch (start) {
+                0 => 0,
+                1 => 1,
+                2 => 2,
+                3 => 3,
+                else => |x| continue :s x / 2,
+            };
+            try expect(result == 2);
+        }
+    };
+    try S.doTheTest();
+    try comptime S.doTheTest();
+}
+
+test "switch loop with ranges" {
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // TODO
+
+    const S = struct {
+        fn doTheTest() !void {
+            var start: u32 = undefined;
+            start = 32;
+            const result = s: switch (start) {
+                0...3 => |x| x,
+                else => |x| continue :s x / 2,
+            };
+            try expect(result == 2);
+        }
+    };
+    try S.doTheTest();
+    try comptime S.doTheTest();
+}
+
+test "switch loop on enum" {
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // TODO
+
+    const S = struct {
+        const E = enum { a, b, c };
+
+        fn doTheTest() !void {
+            var start: E = undefined;
+            start = .a;
+            const result: u32 = s: switch (start) {
+                .a => continue :s .b,
+                .b => continue :s .c,
+                .c => 123,
+            };
+            try expect(result == 123);
+        }
+    };
+    try S.doTheTest();
+    try comptime S.doTheTest();
+}
+
+test "switch loop on tagged union" {
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_riscv64) return error.SkipZigTest;
+
+    const S = struct {
+        const U = union(enum) {
+            a: u32,
+            b: f32,
+            c: f32,
+        };
+
+        fn doTheTest() !void {
+            var start: U = undefined;
+            start = .{ .a = 80 };
+            const result = s: switch (start) {
+                .a => |x| switch (x) {
+                    0...49 => continue :s .{ .b = @floatFromInt(x) },
+                    50 => continue :s .{ .c = @floatFromInt(x) },
+                    else => continue :s .{ .a = x / 2 },
+                },
+                .b => |x| x,
+                .c => return error.TestFailed,
+            };
+            try expect(result == 40.0);
+        }
+    };
+    try S.doTheTest();
+    try comptime S.doTheTest();
+}
+
+test "switch loop dispatching instructions" {
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // TODO
+
+    const S = struct {
+        const Inst = union(enum) {
+            set: u32,
+            add: u32,
+            sub: u32,
+            end,
+        };
+
+        fn doTheTest() !void {
+            var insts: [5]Inst = undefined;
+            @memcpy(&insts, &[5]Inst{
+                .{ .set = 123 },
+                .{ .add = 100 },
+                .{ .sub = 50 },
+                .{ .sub = 10 },
+                .end,
+            });
+            var i: u32 = 0;
+            var cur: u32 = undefined;
+            eval: switch (insts[0]) {
+                .set => |x| {
+                    cur = x;
+                    i += 1;
+                    continue :eval insts[i];
+                },
+                .add => |x| {
+                    cur += x;
+                    i += 1;
+                    continue :eval insts[i];
+                },
+                .sub => |x| {
+                    cur -= x;
+                    i += 1;
+                    continue :eval insts[i];
+                },
+                .end => {},
+            }
+            try expect(cur == 163);
+        }
+    };
+    try S.doTheTest();
+    try comptime S.doTheTest();
+}
+
+test "switch loop with pointer capture" {
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // TODO
+
+    const S = struct {
+        const U = union(enum) {
+            a: u32,
+            b: u32,
+            c: u32,
+        };
+
+        fn doTheTest() !void {
+            var a: U = .{ .a = 100 };
+            var b: U = .{ .b = 200 };
+            var c: U = .{ .c = 300 };
+            inc: switch (a) {
+                .a => |*x| {
+                    x.* += 1;
+                    continue :inc b;
+                },
+                .b => |*x| {
+                    x.* += 10;
+                    continue :inc c;
+                },
+                .c => |*x| {
+                    x.* += 50;
+                },
+            }
+            try expect(a.a == 101);
+            try expect(b.b == 210);
+            try expect(c.c == 350);
+        }
+    };
+    try S.doTheTest();
+    try comptime S.doTheTest();
+}
diff --git a/test/cases/compile_errors/duplicate-unused_labels.zig b/test/cases/compile_errors/duplicate-unused_labels.zig
index 301d273bde..7b22edef20 100644
--- a/test/cases/compile_errors/duplicate-unused_labels.zig
+++ b/test/cases/compile_errors/duplicate-unused_labels.zig
@@ -22,6 +22,11 @@ comptime {
 comptime {
     blk: for (@as([0]void, undefined)) |_| {}
 }
+comptime {
+    blk: switch (true) {
+        else => {},
+    }
+}
 
 // error
 // target=native
@@ -35,3 +40,4 @@ comptime {
 // :17:5: error: unused block label
 // :20:5: error: unused while loop label
 // :23:5: error: unused for loop label
+// :26:5: error: unused switch label