Add x86 legalization for SIMD ineg

cranelift/codegen/meta/src/isa/x86/legalize.rs

@@ -36,6 +36,7 @@ pub(crate) fn define(shared: &mut SharedDefinitions, x86_instructions: &Instruct
     let iadd = insts.by_name("iadd");
     let iconst = insts.by_name("iconst");
     let imul = insts.by_name("imul");
+    let ineg = insts.by_name("ineg");
     let insertlane = insts.by_name("insertlane");
     let isub = insts.by_name("isub");
     let popcnt = insts.by_name("popcnt");
@@ -385,6 +386,7 @@ pub(crate) fn define(shared: &mut SharedDefinitions, x86_instructions: &Instruct
     narrow.custom_legalize(shuffle, "convert_shuffle");
     narrow.custom_legalize(extractlane, "convert_extractlane");
     narrow.custom_legalize(insertlane, "convert_insertlane");
+    narrow.custom_legalize(ineg, "convert_ineg");
 
     narrow.build_and_add_to(&mut shared.transform_groups);
 }

cranelift/codegen/meta/src/shared/instructions.rs

@@ -1704,6 +1704,17 @@ pub(crate) fn define(
         .operands_out(vec![a]),
     );
 
+    ig.push(
+        Inst::new(
+            "ineg",
+            r#"
+        Integer negation: `a := -x \pmod{2^B}`.
+        "#,
+        )
+        .operands_in(vec![x])
+        .operands_out(vec![a]),
+    );
+
     ig.push(
         Inst::new(
             "imul",