target/arm: Convert Neon 3-reg-diff long multiplies

Convert the Neon 3-reg-diff insns VMULL, VMLAL and VMLSL; these perform
a 32x32->64 multiply with possible accumulate.

Note that for VMLSL we do the accumulate directly with a subtraction
rather than doing a negate-then-add as the old code did.

Backports commit 3a1d9eb07b767a7592abca642af80906f9eab0ed from qemu

qemu/target/arm/neon-dp.decode

@@ -450,5 +450,14 @@ Vimm_1r          1111 001 . 1 . 000 ... .... cmode:4 0 . op:1 1 .... @1reg_imm
 
     VABDL_S_3d   1111 001 0 1 . .. .... .... 0111 . 0 . 0 .... @3diff
     VABDL_U_3d   1111 001 1 1 . .. .... .... 0111 . 0 . 0 .... @3diff
+
+    VMLAL_S_3d   1111 001 0 1 . .. .... .... 1000 . 0 . 0 .... @3diff
+    VMLAL_U_3d   1111 001 1 1 . .. .... .... 1000 . 0 . 0 .... @3diff
+
+    VMLSL_S_3d   1111 001 0 1 . .. .... .... 1010 . 0 . 0 .... @3diff
+    VMLSL_U_3d   1111 001 1 1 . .. .... .... 1010 . 0 . 0 .... @3diff
+
+    VMULL_S_3d   1111 001 0 1 . .. .... .... 1100 . 0 . 0 .... @3diff
+    VMULL_U_3d   1111 001 1 1 . .. .... .... 1100 . 0 . 0 .... @3diff
   ]
 }

qemu/target/arm/translate-neon.inc.c

@@ -2178,3 +2178,74 @@ static bool trans_VABAL_U_3d(DisasContext *s, arg_3diff *a)
 
     return do_long_3d(s, a, opfn[a->size], addfn[a->size]);
 }
+
+static void gen_mull_s32(TCGContext *s, TCGv_i64 rd, TCGv_i32 rn, TCGv_i32 rm)
+{
+    TCGv_i32 lo = tcg_temp_new_i32(s);
+    TCGv_i32 hi = tcg_temp_new_i32(s);
+
+    tcg_gen_muls2_i32(s, lo, hi, rn, rm);
+    tcg_gen_concat_i32_i64(s, rd, lo, hi);
+
+    tcg_temp_free_i32(s, lo);
+    tcg_temp_free_i32(s, hi);
+}
+
+static void gen_mull_u32(TCGContext *s, TCGv_i64 rd, TCGv_i32 rn, TCGv_i32 rm)
+{
+    TCGv_i32 lo = tcg_temp_new_i32(s);
+    TCGv_i32 hi = tcg_temp_new_i32(s);
+
+    tcg_gen_mulu2_i32(s, lo, hi, rn, rm);
+    tcg_gen_concat_i32_i64(s, rd, lo, hi);
+
+    tcg_temp_free_i32(s, lo);
+    tcg_temp_free_i32(s, hi);
+}
+
+static bool trans_VMULL_S_3d(DisasContext *s, arg_3diff *a)
+{
+    static NeonGenTwoOpWidenFn * const opfn[] = {
+        gen_helper_neon_mull_s8,
+        gen_helper_neon_mull_s16,
+        gen_mull_s32,
+        NULL,
+    };
+
+    return do_long_3d(s, a, opfn[a->size], NULL);
+}
+
+static bool trans_VMULL_U_3d(DisasContext *s, arg_3diff *a)
+{
+    static NeonGenTwoOpWidenFn * const opfn[] = {
+        gen_helper_neon_mull_u8,
+        gen_helper_neon_mull_u16,
+        gen_mull_u32,
+        NULL,
+    };
+
+    return do_long_3d(s, a, opfn[a->size], NULL);
+}
+
+#define DO_VMLAL(INSN,MULL,ACC)                                         \
+    static bool trans_##INSN##_3d(DisasContext *s, arg_3diff *a)        \
+    {                                                                   \
+        static NeonGenTwoOpWidenFn * const opfn[] = {                   \
+            gen_helper_neon_##MULL##8,                                  \
+            gen_helper_neon_##MULL##16,                                 \
+            gen_##MULL##32,                                             \
+            NULL,                                                       \
+        };                                                              \
+        static NeonGenTwo64OpFn * const accfn[] = {                     \
+            gen_helper_neon_##ACC##l_u16,                               \
+            gen_helper_neon_##ACC##l_u32,                               \
+            tcg_gen_##ACC##_i64,                                        \
+            NULL,                                                       \
+        };                                                              \
+        return do_long_3d(s, a, opfn[a->size], accfn[a->size]);         \
+    }
+
+DO_VMLAL(VMLAL_S,mull_s,add)
+DO_VMLAL(VMLAL_U,mull_u,add)
+DO_VMLAL(VMLSL_S,mull_s,sub)
+DO_VMLAL(VMLSL_U,mull_u,sub)

qemu/target/arm/translate.c

@@ -5370,11 +5370,11 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                     {0, 0, 0, 7}, /* VABAL */
                     {0, 0, 0, 7}, /* VSUBHN: handled by decodetree */
                     {0, 0, 0, 7}, /* VABDL */
-                    {0, 0, 0, 0}, /* VMLAL */
+                    {0, 0, 0, 7}, /* VMLAL */
                     {0, 0, 0, 9}, /* VQDMLAL */
-                    {0, 0, 0, 0}, /* VMLSL */
+                    {0, 0, 0, 7}, /* VMLSL */
                     {0, 0, 0, 9}, /* VQDMLSL */
-                    {0, 0, 0, 0}, /* Integer VMULL */
+                    {0, 0, 0, 7}, /* Integer VMULL */
                     {0, 0, 0, 9}, /* VQDMULL */
                     {0, 0, 0, 0xa}, /* Polynomial VMULL */
                     {0, 0, 0, 7}, /* Reserved: always UNDEF */
@@ -5430,8 +5430,8 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                         tmp2 = neon_load_reg(s, rm, pass);
                     }
                     switch (op) {
-                    case 8: case 9: case 10: case 11: case 12: case 13:
+                    case 9: case 11: case 13:
-                        /* VMLAL, VQDMLAL, VMLSL, VQDMLSL, VMULL, VQDMULL */
+                        /* VQDMLAL, VQDMLSL, VQDMULL */
                         gen_neon_mull(s, s->V0, tmp, tmp2, size, u);
                         break;
                     default: /* 15 is RESERVED: caught earlier  */
@@ -5441,16 +5441,10 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                         /* VQDMULL */
                         gen_neon_addl_saturate(s, s->V0, s->V0, size);
                         neon_store_reg64(s, s->V0, rd + pass);
-                    } else if (op == 5 || (op >= 8 && op <= 11)) {
+                    } else {
                         /* Accumulate.  */
                         neon_load_reg64(s, s->V1, rd + pass);
                         switch (op) {
-                        case 10: /* VMLSL */
-                            gen_neon_negl(s, s->V0, size);
-                            /* Fall through */
-                        case 8: /* VABAL, VMLAL */
-                            gen_neon_addl(s, size);
-                            break;
                         case 9: case 11: /* VQDMLAL, VQDMLSL */
                             gen_neon_addl_saturate(s, s->V0, s->V0, size);
                             if (op == 11) {
@@ -5462,9 +5456,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
                             abort();
                         }
                         neon_store_reg64(s, s->V0, rd + pass);
-                    } else {
-                        /* Write back the result.  */
-                        neon_store_reg64(s, s->V0, rd + pass);
                     }
                 }
             } else {