target/arm: Use gvec for VSHR, VSHL

Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
Message-id: 20181011205206.3552-13-richard.henderson@linaro.org
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target/arm/translate.c

@@ -6373,8 +6373,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                     size--;
             }
             shift = (insn >> 16) & ((1 << (3 + size)) - 1);
-            /* To avoid excessive duplication of ops we implement shift
-               by immediate using the variable shift operations.  */
             if (op < 8) {
                 /* Shift by immediate:
                    VSHR, VSRA, VRSHR, VRSRA, VSRI, VSHL, VQSHL, VQSHLU.  */
@@ -6386,37 +6384,62 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                 }
                 /* Right shifts are encoded as N - shift, where N is the
                    element size in bits.  */
-                if (op <= 4)
+                if (op <= 4) {
                     shift = shift - (1 << (size + 3));
+                }
+
+                switch (op) {
+                case 0:  /* VSHR */
+                    /* Right shift comes here negative.  */
+                    shift = -shift;
+                    /* Shifts larger than the element size are architecturally
+                     * valid.  Unsigned results in all zeros; signed results
+                     * in all sign bits.
+                     */
+                    if (!u) {
+                        tcg_gen_gvec_sari(size, rd_ofs, rm_ofs,
+                                          MIN(shift, (8 << size) - 1),
+                                          vec_size, vec_size);
+                    } else if (shift >= 8 << size) {
+                        tcg_gen_gvec_dup8i(rd_ofs, vec_size, vec_size, 0);
+                    } else {
+                        tcg_gen_gvec_shri(size, rd_ofs, rm_ofs, shift,
+                                          vec_size, vec_size);
+                    }
+                    return 0;
+
+                case 5: /* VSHL, VSLI */
+                    if (!u) { /* VSHL */
+                        /* Shifts larger than the element size are
+                         * architecturally valid and results in zero.
+                         */
+                        if (shift >= 8 << size) {
+                            tcg_gen_gvec_dup8i(rd_ofs, vec_size, vec_size, 0);
+                        } else {
+                            tcg_gen_gvec_shli(size, rd_ofs, rm_ofs, shift,
+                                              vec_size, vec_size);
+                        }
+                        return 0;
+                    }
+                    break;
+                }
+
                 if (size == 3) {
                     count = q + 1;
                 } else {
                     count = q ? 4: 2;
                 }
-                switch (size) {
-                case 0:
-                    imm = (uint8_t) shift;
-                    imm |= imm << 8;
-                    imm |= imm << 16;
-                    break;
-                case 1:
-                    imm = (uint16_t) shift;
-                    imm |= imm << 16;
-                    break;
-                case 2:
-                case 3:
-                    imm = shift;
-                    break;
-                default:
-                    abort();
-                }
+
+                /* To avoid excessive duplication of ops we implement shift
+                 * by immediate using the variable shift operations.
+                  */
+                imm = dup_const(size, shift);
 
                 for (pass = 0; pass < count; pass++) {
                     if (size == 3) {
                         neon_load_reg64(cpu_V0, rm + pass);
                         tcg_gen_movi_i64(cpu_V1, imm);
                         switch (op) {
-                        case 0:  /* VSHR */
                         case 1:  /* VSRA */
                             if (u)
                                 gen_helper_neon_shl_u64(cpu_V0, cpu_V0, cpu_V1);
@@ -6447,6 +6470,8 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                                                          cpu_V0, cpu_V1);
                             }
                             break;
+                        default:
+                            g_assert_not_reached();
                         }
                         if (op == 1 || op == 3) {
                             /* Accumulate.  */
@@ -6475,7 +6500,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                         tmp2 = tcg_temp_new_i32();
                         tcg_gen_movi_i32(tmp2, imm);
                         switch (op) {
-                        case 0:  /* VSHR */
                         case 1:  /* VSRA */
                             GEN_NEON_INTEGER_OP(shl);
                             break;
@@ -6513,6 +6537,8 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                         case 7: /* VQSHL */
                             GEN_NEON_INTEGER_OP_ENV(qshl);
                             break;
+                        default:
+                            g_assert_not_reached();
                         }
                         tcg_temp_free_i32(tmp2);