diff --git a/src/cmd/compile/internal/abi/abiutils.go b/src/cmd/compile/internal/abi/abiutils.go
index feda2153f7f..56e008830fe 100644
--- a/src/cmd/compile/internal/abi/abiutils.go
+++ b/src/cmd/compile/internal/abi/abiutils.go
@@ -214,6 +214,7 @@ func appendParamOffsets(offsets []int64, at int64, t *types.Type) ([]int64, int6
 			for _, f := range t.FieldSlice() {
 				offsets, at = appendParamOffsets(offsets, at, f.Type)
 			}
+			at = align(at, t) // type size is rounded up to its alignment
 		case types.TSLICE:
 			return appendParamOffsets(offsets, at, synthSlice)
 		case types.TSTRING: