tcg: Introduce tcg_out_movext

This is common code in most qemu_{ld,st} slow paths, extending the
input value for the store helper data argument or extending the
return value from the load helper.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 0188152..328e018 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -352,6 +352,69 @@
     siglongjmp(s->jmp_trans, -2);
 }
 
+/**
+ * tcg_out_movext -- move and extend
+ * @s: tcg context
+ * @dst_type: integral type for destination
+ * @dst: destination register
+ * @src_type: integral type for source
+ * @src_ext: extension to apply to source
+ * @src: source register
+ *
+ * Move or extend @src into @dst, depending on @src_ext and the types.
+ */
+static void __attribute__((unused))
+tcg_out_movext(TCGContext *s, TCGType dst_type, TCGReg dst,
+               TCGType src_type, MemOp src_ext, TCGReg src)
+{
+    switch (src_ext) {
+    case MO_UB:
+        tcg_out_ext8u(s, dst, src);
+        break;
+    case MO_SB:
+        tcg_out_ext8s(s, dst_type, dst, src);
+        break;
+    case MO_UW:
+        tcg_out_ext16u(s, dst, src);
+        break;
+    case MO_SW:
+        tcg_out_ext16s(s, dst_type, dst, src);
+        break;
+    case MO_UL:
+    case MO_SL:
+        if (dst_type == TCG_TYPE_I32) {
+            if (src_type == TCG_TYPE_I32) {
+                tcg_out_mov(s, TCG_TYPE_I32, dst, src);
+            } else {
+                tcg_out_extrl_i64_i32(s, dst, src);
+            }
+        } else if (src_type == TCG_TYPE_I32) {
+            if (src_ext & MO_SIGN) {
+                tcg_out_exts_i32_i64(s, dst, src);
+            } else {
+                tcg_out_extu_i32_i64(s, dst, src);
+            }
+        } else {
+            if (src_ext & MO_SIGN) {
+                tcg_out_ext32s(s, dst, src);
+            } else {
+                tcg_out_ext32u(s, dst, src);
+            }
+        }
+        break;
+    case MO_UQ:
+        tcg_debug_assert(TCG_TARGET_REG_BITS == 64);
+        if (dst_type == TCG_TYPE_I32) {
+            tcg_out_extrl_i64_i32(s, dst, src);
+        } else {
+            tcg_out_mov(s, TCG_TYPE_I64, dst, src);
+        }
+        break;
+    default:
+        g_assert_not_reached();
+    }
+}
+
 #define C_PFX1(P, A)                    P##A
 #define C_PFX2(P, A, B)                 P##A##_##B
 #define C_PFX3(P, A, B, C)              P##A##_##B##_##C