Add x86 pack instructions

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

@@ -6,7 +6,6 @@ use crate::cdsl::instructions::{
 use crate::cdsl::operands::Operand;
 use crate::cdsl::types::ValueType;
 use crate::cdsl::typevar::{Interval, TypeSetBuilder, TypeVar};
-
 use crate::shared::entities::EntityRefs;
 use crate::shared::formats::Formats;
 use crate::shared::immediates::Immediates;
@@ -275,7 +274,7 @@ pub(crate) fn define(
     );
     let a = &Operand::new("a", TxN).with_doc("A vector value (i.e. held in an XMM register)");
     let b = &Operand::new("b", TxN).with_doc("A vector value (i.e. held in an XMM register)");
-    let i = &Operand::new("i", uimm8,).with_doc( "An ordering operand controlling the copying of data from the source to the destination; see PSHUFD in Intel manual for details");
+    let i = &Operand::new("i", uimm8).with_doc("An ordering operand controlling the copying of data from the source to the destination; see PSHUFD in Intel manual for details");
 
     ig.push(
         Inst::new(
@@ -410,6 +409,35 @@ pub(crate) fn define(
         .operands_out(vec![a]),
     );
 
+    let I16xN = &TypeVar::new(
+        "I16xN",
+        "A SIMD vector type containing integers 16-bits wide and up",
+        TypeSetBuilder::new()
+            .ints(16..32)
+            .simd_lanes(4..8)
+            .includes_scalars(false)
+            .build(),
+    );
+
+    let x = &Operand::new("x", I16xN);
+    let y = &Operand::new("y", I16xN);
+    let a = &Operand::new("a", &I16xN.split_lanes());
+
+    ig.push(
+        Inst::new(
+            "x86_packss",
+            r#"
+        Convert packed signed integers the lanes of ``x`` and ``y`` into half-width integers, using
+        signed saturation to handle overflows. For example, with notional i16x2 vectors, where 
+        ``x = [x1, x0]`` and ``y = [y1, y0]``, this operation would result in 
+        ``a = [y1', y0', x1', x0']`` (using the Intel manual's right-to-left lane ordering).
+        "#,
+            &formats.binary,
+        )
+        .operands_in(vec![x, y])
+        .operands_out(vec![a]),
+    );
+
     let x = &Operand::new("x", FxN);
     let y = &Operand::new("y", FxN);
     let a = &Operand::new("a", FxN);