tcg-ia64: Define TCG_TARGET_INSN_UNIT_SIZE

Using a 16-byte aligned structure achieves best results, both for code
cleanliness and compiled code size.  However, this means that we can't
use the trick of encoding the slot number into the low 2 bits.

Thankfully, we only ever use slot2, so make that explicit in the names
of the relocation functions, and drop the code for other slots.

Signed-off-by: Richard Henderson <rth@twiddle.net>

tcg/ia64/tcg-target.h

@@ -25,6 +25,12 @@
 #ifndef TCG_TARGET_IA64 
 #define TCG_TARGET_IA64 1
 
+#define TCG_TARGET_INSN_UNIT_SIZE 16
+typedef struct {
+    uint64_t lo __attribute__((aligned(16)));
+    uint64_t hi;
+} tcg_insn_unit;
+
 /* We only map the first 64 registers */
 #define TCG_TARGET_NB_REGS 64
 typedef enum {