Use andn for band_not when bmi1 is present (#5701)

We can use the andn instruction for the lowering of band_not on x64 when bmi1 is available.

cranelift/codegen/src/isa/x64/inst/args.rs

@@ -745,7 +745,7 @@ impl PrettyPrint for RegMem {
     }
 }
 
-/// Some basic ALU operations.  TODO: maybe add Adc, Sbb.
+/// Some basic ALU operations.
 #[derive(Copy, Clone, PartialEq)]
 pub enum AluRmiROpcode {
     /// Add operation.
@@ -788,6 +788,36 @@ impl fmt::Display for AluRmiROpcode {
     }
 }
 
+/// ALU operations that don't accept intermediates.
+#[derive(Copy, Clone, PartialEq)]
+pub enum AluRmROpcode {
+    /// And with negated second operand.
+    Andn,
+}
+
+impl AluRmROpcode {
+    pub(crate) fn available_from(&self) -> SmallVec<[InstructionSet; 2]> {
+        match self {
+            AluRmROpcode::Andn => smallvec![InstructionSet::BMI1],
+        }
+    }
+}
+
+impl fmt::Debug for AluRmROpcode {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        let name = match self {
+            AluRmROpcode::Andn => "andn",
+        };
+        write!(fmt, "{}", name)
+    }
+}
+
+impl fmt::Display for AluRmROpcode {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(self, f)
+    }
+}
+
 #[derive(Clone, PartialEq)]
 /// Unary operations requiring register or memory and register operands.
 pub enum UnaryRmROpcode {