diff --git a/src/arch/x86_64/CodeGen.zig b/src/arch/x86_64/CodeGen.zig
index 7faf3d6d50..cc6e014080 100644
--- a/src/arch/x86_64/CodeGen.zig
+++ b/src/arch/x86_64/CodeGen.zig
@@ -14318,7 +14318,7 @@ fn moveStrategy(self: *Self, ty: Type, class: Register.Class, aligned: bool) !Mo
             else => {
                 const classes = mem.sliceTo(&abi.classifySystemV(ty, mod, self.target.*, .other), .none);
                 assert(std.mem.indexOfNone(abi.Class, classes, &.{
-                    .integer, .sse, .memory, .float, .float_combine,
+                    .integer, .sse, .sseup, .memory, .float, .float_combine,
                 }) == null);
                 const abi_size = ty.abiSize(mod);
                 if (abi_size < 4 or
diff --git a/src/arch/x86_64/abi.zig b/src/arch/x86_64/abi.zig
index 8c81ad9ed2..0ae69eb09c 100644
--- a/src/arch/x86_64/abi.zig
+++ b/src/arch/x86_64/abi.zig
@@ -170,10 +170,6 @@ pub fn classifySystemV(ty: Type, zcu: *Zcu, target: std.Target, ctx: Context) [8
                 // "Arguments of types __float128, _Decimal128 and __m128 are
                 // split into two halves.  The least significant ones belong
                 // to class SSE, the most significant one to class SSEUP."
-                if (ctx == .field) {
-                    result[0] = .memory;
-                    return result;
-                }
                 result[0] = .sse;
                 result[1] = .sseup;
                 return result;
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 877b2365c8..2d3c7de2e2 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -11167,10 +11167,18 @@ fn lowerSystemVFnRetTy(o: *Object, fn_info: InternPool.Key.FuncType) Allocator.E
                 types_buffer[types_index] = .i64;
                 types_index += 1;
             },
-            .sse, .sseup => {
+            .sse => {
                 types_buffer[types_index] = .double;
                 types_index += 1;
             },
+            .sseup => {
+                if (types_buffer[types_index - 1] == .double) {
+                    types_buffer[types_index - 1] = .fp128;
+                } else {
+                    types_buffer[types_index] = .double;
+                    types_index += 1;
+                }
+            },
             .float => {
                 types_buffer[types_index] = .float;
                 types_index += 1;
@@ -11454,10 +11462,18 @@ const ParamTypeIterator = struct {
                     types_buffer[types_index] = .i64;
                     types_index += 1;
                 },
-                .sse, .sseup => {
+                .sse => {
                     types_buffer[types_index] = .double;
                     types_index += 1;
                 },
+                .sseup => {
+                    if (types_buffer[types_index - 1] == .double) {
+                        types_buffer[types_index - 1] = .fp128;
+                    } else {
+                        types_buffer[types_index] = .double;
+                        types_index += 1;
+                    }
+                },
                 .float => {
                     types_buffer[types_index] = .float;
                     types_index += 1;