target/arm: Convert Neon 3-reg-diff polynomial VMULL

Convert the Neon 3-reg-diff insn polynomial VMULL. This is the last
insn in this group to be converted.

Backports commit 18fb58d588898550919392277787979ee7d0d84e from qemu

qemu/target/arm/neon-dp.decode

@@ -465,5 +465,7 @@ Vimm_1r          1111 001 . 1 . 000 ... .... cmode:4 0 . op:1 1 .... @1reg_imm
     VMULL_U_3d   1111 001 1 1 . .. .... .... 1100 . 0 . 0 .... @3diff
 
     VQDMULL_3d   1111 001 0 1 . .. .... .... 1101 . 0 . 0 .... @3diff
+
+    VMULL_P_3d   1111 001 0 1 . .. .... .... 1110 . 0 . 0 .... @3diff
   ]
 }

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

@@ -2331,3 +2331,47 @@ static bool trans_VQDMLSL_3d(DisasContext *s, arg_3diff *a)
 
     return do_long_3d(s, a, opfn[a->size], accfn[a->size]);
 }
+
+static bool trans_VMULL_P_3d(DisasContext *s, arg_3diff *a)
+{
+    TCGContext *tcg_ctx = s->uc->tcg_ctx;
+    gen_helper_gvec_3 *fn_gvec;
+
+    if (!arm_dc_feature(s, ARM_FEATURE_NEON)) {
+        return false;
+    }
+
+    /* UNDEF accesses to D16-D31 if they don't exist. */
+    if (!dc_isar_feature(aa32_simd_r32, s) &&
+        ((a->vd | a->vn | a->vm) & 0x10)) {
+        return false;
+    }
+
+    if (a->vd & 1) {
+        return false;
+    }
+
+    switch (a->size) {
+    case 0:
+        fn_gvec = gen_helper_neon_pmull_h;
+        break;
+    case 2:
+        if (!dc_isar_feature(aa32_pmull, s)) {
+            return false;
+        }
+        fn_gvec = gen_helper_gvec_pmull_q;
+        break;
+    default:
+        return false;
+    }
+
+    if (!vfp_access_check(s)) {
+        return true;
+    }
+
+    tcg_gen_gvec_3_ool(tcg_ctx, neon_reg_offset(a->vd, 0),
+                       neon_reg_offset(a->vn, 0),
+                       neon_reg_offset(a->vm, 0),
+                       16, 16, 0, fn_gvec);
+    return true;
+}

qemu/target/arm/translate.c

@@ -5305,7 +5305,7 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
     TCGContext *tcg_ctx = s->uc->tcg_ctx;
     int op;
     int q;
-    int rd, rn, rm, rd_ofs, rn_ofs, rm_ofs;
+    int rd, rn, rm, rd_ofs, rm_ofs;
     int size;
     int pass;
     int u;
@@ -5339,7 +5339,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
     size = (insn >> 20) & 3;
     vec_size = q ? 16 : 8;
     rd_ofs = neon_reg_offset(rd, 0);
-    rn_ofs = neon_reg_offset(rn, 0);
     rm_ofs = neon_reg_offset(rm, 0);
 
     if ((insn & (1 << 23)) == 0) {
@@ -5352,62 +5351,8 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
         if (size != 3) {
             op = (insn >> 8) & 0xf;
             if ((insn & (1 << 6)) == 0) {
-                /* Three registers of different lengths.  */
+                /* Three registers of different lengths: handled by decodetree */
-                /* undefreq: bit 0 : UNDEF if size == 0
+                return 1;
-                 *           bit 1 : UNDEF if size == 1
-                 *           bit 2 : UNDEF if size == 2
-                 *           bit 3 : UNDEF if U == 1
-                 * Note that [2:0] set implies 'always UNDEF'
-                 */
-                int undefreq;
-                /* prewiden, src1_wide, src2_wide, undefreq */
-                static const int neon_3reg_wide[16][4] = {
-                    {0, 0, 0, 7}, /* VADDL: handled by decodetree */
-                    {0, 0, 0, 7}, /* VADDW: handled by decodetree */
-                    {0, 0, 0, 7}, /* VSUBL: handled by decodetree */
-                    {0, 0, 0, 7}, /* VSUBW: handled by decodetree */
-                    {0, 0, 0, 7}, /* VADDHN: handled by decodetree */
-                    {0, 0, 0, 7}, /* VABAL */
-                    {0, 0, 0, 7}, /* VSUBHN: handled by decodetree */
-                    {0, 0, 0, 7}, /* VABDL */
-                    {0, 0, 0, 7}, /* VMLAL */
-                    {0, 0, 0, 7}, /* VQDMLAL */
-                    {0, 0, 0, 7}, /* VMLSL */
-                    {0, 0, 0, 7}, /* VQDMLSL */
-                    {0, 0, 0, 7}, /* Integer VMULL */
-                    {0, 0, 0, 7}, /* VQDMULL */
-                    {0, 0, 0, 0xa}, /* Polynomial VMULL */
-                    {0, 0, 0, 7}, /* Reserved: always UNDEF */
-                };
-
-                undefreq = neon_3reg_wide[op][3];
-
-                if ((undefreq & (1 << size)) ||
-                    ((undefreq & 8) && u)) {
-                    return 1;
-                }
-                if (rd & 1) {
-                    return 1;
-                }
-
-                /* Handle polynomial VMULL in a single pass.  */
-                if (op == 14) {
-                    if (size == 0) {
-                        /* VMULL.P8 */
-                        tcg_gen_gvec_3_ool(tcg_ctx, rd_ofs, rn_ofs, rm_ofs, 16, 16,
-                                           0, gen_helper_neon_pmull_h);
-                    } else {
-                        /* VMULL.P64 */
-                        if (!dc_isar_feature(aa32_pmull, s)) {
-                            return 1;
-                        }
-                        tcg_gen_gvec_3_ool(tcg_ctx, rd_ofs, rn_ofs, rm_ofs, 16, 16,
-                                           0, gen_helper_gvec_pmull_q);
-                    }
-                    return 0;
-                }
-
-                abort(); /* all others handled by decodetree */
             } else {
                 /* Two registers and a scalar. NB that for ops of this form
                  * the ARM ARM labels bit 24 as Q, but it is in our variable