Merge pull request ziglang#17438 from Luukdegram/issue-17436

wasm - fix `@tagName` for signed enums

Author: Luukdegram

src/arch/wasm/CodeGen.zig

@@ -7215,12 +7215,12 @@ fn getTagNameFunction(func: *CodeGen, enum_ty: Type) InnerError!u32 {
         switch (tag_value) {
             .imm32 => |value| {
                 try writer.writeByte(std.wasm.opcode(.i32_const));
-                try leb.writeULEB128(writer, value);
+                try leb.writeILEB128(writer, @as(i32, @bitCast(value)));
                 try writer.writeByte(std.wasm.opcode(.i32_ne));
             },
             .imm64 => |value| {
                 try writer.writeByte(std.wasm.opcode(.i64_const));
-                try leb.writeULEB128(writer, value);
+                try leb.writeILEB128(writer, @as(i64, @bitCast(value)));
                 try writer.writeByte(std.wasm.opcode(.i64_ne));
             },
             else => unreachable,

test/behavior/enum.zig

@@ -1048,6 +1048,22 @@ test "@tagName on enum literals" {
     try comptime expect(mem.eql(u8, @tagName(.FooBar), "FooBar"));
 }
 
+test "tag name with signed enum values" {
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
+
+    const LocalFoo = enum(isize) {
+        alfa = 62,
+        bravo = 63,
+        charlie = 64,
+        delta = 65,
+    };
+    var b = LocalFoo.bravo;
+    try expect(mem.eql(u8, @tagName(b), "bravo"));
+}
+
 test "enum literal casting to optional" {
     if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
     if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;