diff --git a/cranelift/filetests/filetests/runtests/extend.clif b/cranelift/filetests/filetests/runtests/extend.clif
index dc89220aa4b2..524177de1054 100644
--- a/cranelift/filetests/filetests/runtests/extend.clif
+++ b/cranelift/filetests/filetests/runtests/extend.clif
@@ -2,17 +2,14 @@ test run
 target aarch64
 target arm
 target s390x
-; target x86_64 TODO: Not yet implemented on x86_64
+target x86_64
 
 function %uextend() -> b1 {
 block0:
     v0 = iconst.i32 0xffff_ee00
     v1 = uextend.i64 v0
-    v2, v3 = isplit v1
-    v4 = icmp_imm eq v2, 0xffff_ee00
-    v5 = icmp_imm eq v3, 0
-    v6 = band v4, v5
-    return v6
+    v2 = icmp_imm eq v1, 0xffff_ee00
+    return v2
 }
 ; run
 
@@ -20,10 +17,7 @@ function %sextend() -> b1 {
 block0:
     v0 = iconst.i32 0xffff_ee00
     v1 = sextend.i64 v0
-    v2, v3 = isplit v1
-    v4 = icmp_imm eq v2, 0xffff_ee00
-    v5 = icmp_imm eq v3, 0xffff_ffff
-    v6 = band v4, v5
-    return v6
+    v2 = icmp_imm eq v1, 0xffff_ffff_ffff_ee00
+    return v2
 }
 ; run