From d62229e3ad6069597b74874ba3b84fc185b2fa4c Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Sat, 26 Feb 2022 15:35:46 -0700
Subject: [PATCH] Sema: Module.Union.abiAlignment can return 0

When the union is a 0-bit type.
---
 src/Module.zig            |  2 +-
 test/behavior/floatop.zig | 34 ++++++++++++++++------------------
 test/behavior/union.zig   |  4 +++-
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/src/Module.zig b/src/Module.zig
index 7f52dc23e94b27566f65c49ed1a885a9895940df..91386405be0564b3fe4e3761ea177b76fd1e5618 100644
--- a/src/Module.zig
+++ b/src/Module.zig
@@ -1210,6 +1210,7 @@ pub const Union = struct {
         return @intCast(u32, most_index);
     }
 
+    /// Returns 0 if the union is represented with 0 bits at runtime.
     pub fn abiAlignment(u: Union, target: Target, have_tag: bool) u32 {
         var max_align: u32 = 0;
         if (have_tag) max_align = u.tag_ty.abiAlignment(target);
@@ -1225,7 +1226,6 @@ pub const Union = struct {
             };
             max_align = @maximum(max_align, field_align);
         }
-        assert(max_align != 0);
         return max_align;
     }
 
diff --git a/test/behavior/floatop.zig b/test/behavior/floatop.zig
index 85d5cec1e6d48d84c28ab9d322e30bce801baf78..5597be122e588522ddbb4f57dc7608e37361beeb 100644
--- a/test/behavior/floatop.zig
+++ b/test/behavior/floatop.zig
@@ -155,15 +155,14 @@ test "@sin" {
 
 fn testSin() !void {
     // stage1 emits an incorrect compile error for `@as(ty, std.math.pi / 2)`
-    // so skip the rest of the tests.
-    if (builtin.zig_backend != .stage1) {
-        inline for ([_]type{ f16, f32, f64 }) |ty| {
-            const eps = epsForType(ty);
-            try expect(@sin(@as(ty, 0)) == 0);
-            try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi)), 0, eps));
-            try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi / 2)), 1, eps));
-            try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi / 4)), 0.7071067811865475, eps));
-        }
+    if (builtin.zig_backend == .stage1) return error.SkipZigTest;
+
+    inline for ([_]type{ f16, f32, f64 }) |ty| {
+        const eps = epsForType(ty);
+        try expect(@sin(@as(ty, 0)) == 0);
+        try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi)), 0, eps));
+        try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi / 2)), 1, eps));
+        try expect(math.approxEqAbs(ty, @sin(@as(ty, std.math.pi / 4)), 0.7071067811865475, eps));
     }
 
     {
@@ -183,15 +182,14 @@ test "@cos" {
 
 fn testCos() !void {
     // stage1 emits an incorrect compile error for `@as(ty, std.math.pi / 2)`
-    // so skip the rest of the tests.
-    if (builtin.zig_backend != .stage1) {
-        inline for ([_]type{ f16, f32, f64 }) |ty| {
-            const eps = epsForType(ty);
-            try expect(@cos(@as(ty, 0)) == 1);
-            try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi)), -1, eps));
-            try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi / 2)), 0, eps));
-            try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi / 4)), 0.7071067811865475, eps));
-        }
+    if (builtin.zig_backend == .stage1) return error.SkipZigTest;
+
+    inline for ([_]type{ f16, f32, f64 }) |ty| {
+        const eps = epsForType(ty);
+        try expect(@cos(@as(ty, 0)) == 1);
+        try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi)), -1, eps));
+        try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi / 2)), 0, eps));
+        try expect(math.approxEqAbs(ty, @cos(@as(ty, std.math.pi / 4)), 0.7071067811865475, eps));
     }
 
     {
diff --git a/test/behavior/union.zig b/test/behavior/union.zig
index 7f78ca9adf51a25d06ab2545171386edc824c84b..a3549e9599954fdb02ef509999fe00e38e8acf7b 100644
--- a/test/behavior/union.zig
+++ b/test/behavior/union.zig
@@ -648,7 +648,9 @@ fn testEnumWithSpecifiedAndUnspecifiedTagValues(x: MultipleChoice2) !void {
 }
 
 test "switch on union with only 1 field" {
-    if (builtin.zig_backend != .stage1) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
 
     var r: PartialInst = undefined;
     r = PartialInst.Compiled;
-- 
2.54.0