zig

commit daf3cca1a491636dcd2cde45b12bc3bfcfbab69c (tree)
parent 47e208e554776aa4f5f3fe74d6f8d995efa3aaad
Author: Alex Rønne Petersen <alex@alexrp.com>
Date:   Mon, 15 Jun 2026 14:17:03 +0200

compiler: fix struct field alignment for big ints on s390x

contributes to https://codeberg.org/ziglang/zig/issues/35523

Diffstat:
M
src/Type.zig
 | 
2
+-
M
test/behavior/align.zig
 | 
17
+++++++++++++++--

2 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/src/Type.zig b/src/Type.zig
@@ -2521,7 +2521,7 @@ pub fn defaultStructFieldAlignment(
         ((field_ty.isAbiInt(zcu) and field_ty.intInfo(zcu).bits > 64) or
             (field_ty.toIntern() == .f80_type and zcu.getTarget().cTypeBitSize(.longdouble) != 80)))
     {
-        return abi_align.maxStrict(.@"16");
+        return abi_align.maxStrict(if (zcu.getTarget().cpu.arch == .s390x) .@"8" else .@"16");
     }
     return abi_align;
 }
diff --git a/test/behavior/align.zig b/test/behavior/align.zig
@@ -133,6 +133,20 @@ test "alignment and size of structs with 128-bit fields" {
         y: u8,
     };
     const expected = switch (builtin.cpu.arch) {
+        .s390x,
+        => .{
+            .a_align = 8,
+            .a_size = 16,
+
+            .b_align = 8,
+            .b_size = 24,
+
+            .u128_align = 8,
+            .u128_size = 16,
+            .u129_align = 8,
+            .u129_size = 24,
+        },
+
         .amdgcn,
         .arm,
         .armeb,
@@ -145,7 +159,6 @@ test "alignment and size of structs with 128-bit fields" {
         .powerpc,
         .powerpcle,
         .riscv32,
-        .s390x,
         => .{
             .a_align = 8,
             .a_size = 16,
@@ -191,7 +204,7 @@ test "alignment and size of structs with 128-bit fields" {
 
         else => return error.SkipZigTest,
     };
-    const min_struct_align = if (builtin.zig_backend == .stage2_c) 16 else 0;
+    const min_struct_align = if (builtin.zig_backend == .stage2_c) if (builtin.cpu.arch == .s390x) 8 else 16 else 0;
     comptime {
         assert(@alignOf(A) == @max(expected.a_align, min_struct_align));
         assert(@sizeOf(A) == expected.a_size);