target/arm: Convert Neon VSHLL, VMOVL to decodetree

Convert the VSHLL and VMOVL insns from the 2-reg-shift group
to decodetree. Since the loop always has two passes, we unroll
it to avoid the awkward reassignment of one TCGv to another.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200522145520.6778-8-peter.maydell@linaro.org

1 files changed, 2 insertions, 44 deletions

diff --git a/target/arm/translate.c b/target/arm/translate.c
index 883c1a2..a9f5204 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -5248,6 +5248,7 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
             case 7: /* VQSHL */
             case 8: /* VSHRN, VRSHRN, VQSHRUN, VQRSHRUN */
             case 9: /* VQSHRN, VQRSHRN */
+            case 10: /* VSHLL, including VMOVL */
                 return 1; /* handled by decodetree */
             default:
                 break;
@@ -5265,50 +5266,7 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                     size--;
             }
             shift = (insn >> 16) & ((1 << (3 + size)) - 1);
-            if (op == 10) {
-                /* VSHLL, VMOVL */
-                if (q || (rd & 1)) {
-                    return 1;
-                }
-                tmp = neon_load_reg(rm, 0);
-                tmp2 = neon_load_reg(rm, 1);
-                for (pass = 0; pass < 2; pass++) {
-                    if (pass == 1)
-                        tmp = tmp2;
-
-                    gen_neon_widen(cpu_V0, tmp, size, u);
-
-                    if (shift != 0) {
-                        /* The shift is less than the width of the source
-                           type, so we can just shift the whole register.  */
-                        tcg_gen_shli_i64(cpu_V0, cpu_V0, shift);
-                        /* Widen the result of shift: we need to clear
-                         * the potential overflow bits resulting from
-                         * left bits of the narrow input appearing as
-                         * right bits of left the neighbour narrow
-                         * input.  */
-                        if (size < 2 || !u) {
-                            uint64_t imm64;
-                            if (size == 0) {
-                                imm = (0xffu >> (8 - shift));
-                                imm |= imm << 16;
-                            } else if (size == 1) {
-                                imm = 0xffff >> (16 - shift);
-                            } else {
-                                /* size == 2 */
-                                imm = 0xffffffff >> (32 - shift);
-                            }
-                            if (size < 2) {
-                                imm64 = imm | (((uint64_t)imm) << 32);
-                            } else {
-                                imm64 = imm;
-                            }
-                            tcg_gen_andi_i64(cpu_V0, cpu_V0, ~imm64);
-                        }
-                    }
-                    neon_store_reg64(cpu_V0, rd + pass);
-                }
-            } else if (op >= 14) {
+            if (op >= 14) {
                 /* VCVT fixed-point.  */
                 TCGv_ptr fpst;
                 TCGv_i32 shiftv;