s390x/tcg: Implement VECTOR LOAD VR ELEMENT FROM GR

Very similar to VECTOR LOAD GR FROM VR ELEMENT, just the opposite
direction. Also provide a fast path in case we don't care about the
register content.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190307121539.12842-16-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

target/s390x/insn-data.def

@@ -1004,6 +1004,8 @@
     F(0xe736, VLM,     VRS_a, V,   la2, 0, 0, 0, vlm, 0, IF_VEC)
 /* VECTOR LOAD TO BLOCK BOUNDARY */
     F(0xe707, VLBB,    VRX,   V,   la2, 0, 0, 0, vlbb, 0, IF_VEC)
+/* VECTOR LOAD VR ELEMENT FROM GR */
+    F(0xe722, VLVG,    VRS_b, V,   la2, r3, 0, 0, vlvg, 0, IF_VEC)
 
 #ifndef CONFIG_USER_ONLY
 /* COMPARE AND SWAP AND PURGE */

target/s390x/translate_vx.inc.c

@@ -471,3 +471,44 @@ static DisasJumpType op_vlbb(DisasContext *s, DisasOps *o)
     tcg_temp_free_ptr(a0);
     return DISAS_NEXT;
 }
+
+static DisasJumpType op_vlvg(DisasContext *s, DisasOps *o)
+{
+    const uint8_t es = get_field(s->fields, m4);
+    TCGv_ptr ptr;
+
+    if (es > ES_64) {
+        gen_program_exception(s, PGM_SPECIFICATION);
+        return DISAS_NORETURN;
+    }
+
+    /* fast path if we don't need the register content */
+    if (!get_field(s->fields, b2)) {
+        uint8_t enr = get_field(s->fields, d2) & (NUM_VEC_ELEMENTS(es) - 1);
+
+        write_vec_element_i64(o->in2, get_field(s->fields, v1), enr, es);
+        return DISAS_NEXT;
+    }
+
+    ptr = tcg_temp_new_ptr();
+    get_vec_element_ptr_i64(ptr, get_field(s->fields, v1), o->addr1, es);
+    switch (es) {
+    case ES_8:
+        tcg_gen_st8_i64(o->in2, ptr, 0);
+        break;
+    case ES_16:
+        tcg_gen_st16_i64(o->in2, ptr, 0);
+        break;
+    case ES_32:
+        tcg_gen_st32_i64(o->in2, ptr, 0);
+        break;
+    case ES_64:
+        tcg_gen_st_i64(o->in2, ptr, 0);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+    tcg_temp_free_ptr(ptr);
+
+    return DISAS_NEXT;
+}