llvm: fix C ABI for <=256 bit vectors

Closes #13918

3 files changed, 32 insertions, 1 deletions

diff --git a/src/arch/x86_64/abi.zig b/src/arch/x86_64/abi.zig
index 393d4db3d5..54c08e4aa9 100644
--- a/src/arch/x86_64/abi.zig
+++ b/src/arch/x86_64/abi.zig
@@ -143,7 +143,8 @@ pub fn classifySystemV(ty: Type, target: Target, ctx: Context) [8]Class {
                         .integer, .integer, .integer, .integer,
                         .integer, .integer, .integer, .integer,
                     };
-                    if (has_avx512 and bit_size <= 256) return .{
+                    const has_avx = target.cpu.features.isEnabled(@enumToInt(std.Target.x86.Feature.avx));
+                    if (has_avx and bit_size <= 256) return .{
                         .integer, .integer, .integer, .integer,
                         .none,    .none,    .none,    .none,
                     };
diff --git a/test/c_abi/cfuncs.c b/test/c_abi/cfuncs.c
index 20896669fe..16851f1c7e 100644
--- a/test/c_abi/cfuncs.c
+++ b/test/c_abi/cfuncs.c
@@ -742,6 +742,19 @@ SmallVec c_ret_small_vec(void) {
     return (SmallVec){3, 4};
 }
 
+typedef size_t MediumVec __attribute__((vector_size(4 * sizeof(size_t))));
+
+void c_medium_vec(MediumVec vec) {
+    assert_or_panic(vec[0] == 1);
+    assert_or_panic(vec[1] == 2);
+    assert_or_panic(vec[2] == 3);
+    assert_or_panic(vec[3] == 4);
+}
+
+MediumVec c_ret_medium_vec(void) {
+    return (MediumVec){5, 6, 7, 8};
+}
+
 typedef size_t BigVec __attribute__((vector_size(8 * sizeof(size_t))));
 
 void c_big_vec(BigVec vec) {
diff --git a/test/c_abi/main.zig b/test/c_abi/main.zig
index 47f0455744..dcf4cbe46f 100644
--- a/test/c_abi/main.zig
+++ b/test/c_abi/main.zig
@@ -801,6 +801,23 @@ test "small simd vector" {
     try expect(x[1] == 4);
 }
 
+const MediumVec = @Vector(4, usize);
+
+extern fn c_medium_vec(MediumVec) void;
+extern fn c_ret_medium_vec() MediumVec;
+
+test "medium simd vector" {
+    if (comptime builtin.cpu.arch.isPPC64()) return error.SkipZigTest;
+
+    c_medium_vec(.{ 1, 2, 3, 4 });
+
+    var x = c_ret_medium_vec();
+    try expect(x[0] == 5);
+    try expect(x[1] == 6);
+    try expect(x[2] == 7);
+    try expect(x[3] == 8);
+}
+
 const BigVec = @Vector(8, usize);
 
 extern fn c_big_vec(BigVec) void;