diff --git a/cranelift/codegen/meta/src/cdsl/instructions.rs b/cranelift/codegen/meta/src/cdsl/instructions.rs
index 5f91771797..b91d9f26cf 100644
--- a/cranelift/codegen/meta/src/cdsl/instructions.rs
+++ b/cranelift/codegen/meta/src/cdsl/instructions.rs
@@ -14,7 +14,7 @@ use crate::cdsl::type_inference::Constraint;
 use crate::cdsl::types::{LaneType, ReferenceType, ValueType, VectorType};
 use crate::cdsl::typevar::TypeVar;
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct OpcodeNumber(u32);
 entity_impl!(OpcodeNumber);
 
diff --git a/cranelift/codegen/meta/src/shared/legalize.rs b/cranelift/codegen/meta/src/shared/legalize.rs
index 63118033a9..e006452b35 100644
--- a/cranelift/codegen/meta/src/shared/legalize.rs
+++ b/cranelift/codegen/meta/src/shared/legalize.rs
@@ -247,16 +247,16 @@ pub(crate) fn define(insts: &InstructionGroup, imm: &Immediates) -> TransformGro
             def!((xl, xh) = isplit(x)),
             def!(
                 a = icmp_imm(
-                    Literal::enumerator_for(intcc, "eq"),
+                    Literal::enumerator_for(&imm.intcc, "eq"),
                     xl,
-                    Literal::constant(imm64, 0)
+                    Literal::constant(&imm.imm64, 0)
                 )
             ),
             def!(
                 b = icmp_imm(
-                    Literal::enumerator_for(intcc, "eq"),
+                    Literal::enumerator_for(&imm.intcc, "eq"),
                     xh,
-                    Literal::constant(imm64, 0)
+                    Literal::constant(&imm.imm64, 0)
                 )
             ),
             def!(c = band(a, b)),
@@ -273,6 +273,30 @@ pub(crate) fn define(insts: &InstructionGroup, imm: &Immediates) -> TransformGro
         ],
     );
 
+    // FIXME generalize to any offset once offset+8 can be represented
+    narrow.legalize(
+        def!(a = load.I128(flags, ptr, Literal::constant(&imm.offset32, 0))),
+        vec![
+            def!(al = load.I64(flags, ptr, Literal::constant(&imm.offset32, 0))),
+            def!(ah = load.I64(flags, ptr, Literal::constant(&imm.offset32, 8))),
+            // `iconcat` expects the same byte order as stored in memory,
+            // so no need to swap depending on endianness.
+            def!(a = iconcat(al, ah)),
+        ],
+    );
+
+    // FIXME generalize to any offset once offset+8 can be represented
+    narrow.legalize(
+        def!(store.I128(flags, a, ptr, Literal::constant(&imm.offset32, 0))),
+        vec![
+            // `isplit` gives the same byte order as stored in memory,
+            // so no need to swap depending on endianness.
+            def!((al, ah) = isplit(a)),
+            def!(store.I64(flags, al, ptr, Literal::constant(&imm.offset32, 0))),
+            def!(store.I64(flags, ah, ptr, Literal::constant(&imm.offset32, 8))),
+        ],
+    );
+
     // Widen instructions with one input operand.
     for &op in &[bnot, popcnt] {
         for &int_ty in &[I8, I16] {
diff --git a/cranelift/filetests/filetests/isa/x86/i128.clif b/cranelift/filetests/filetests/isa/x86/i128.clif
index 3c50d219dc..044b01e58f 100644
--- a/cranelift/filetests/filetests/isa/x86/i128.clif
+++ b/cranelift/filetests/filetests/isa/x86/i128.clif
@@ -26,3 +26,21 @@ ebb0(v0: i128):
     ; check: v6 = x86_pop.i64
     ; check: return v3, v4, v6
 }
+
+function u0:1(i64, i128) fast {
+; check: ebb0(v0: i64 [%rdi], v2: i64 [%rsi], v3: i64 [%rdx], v4: i64 [%rbp]):
+ebb0(v0: i64, v1: i128):
+    ; check: store v2, v0
+    ; check: store v3, v0+8
+    store v1, v0
+    return
+}
+
+function u0:1(i64) -> i128 fast {
+ebb0(v0: i64):
+    ; check: v2 = load.i64 v0
+    ; check: v3 = load.i64 v0+8
+    v1 = load.i128 v0
+    ; check: return v2, v3, v5
+    return v1
+}