Hexagon (target/hexagon) Remove old way of detecting register multiwrites

We now detect register multiwrites in packet analysis instead of
packet decoding

Reviewed-by: Brian Cain <brian.cain@oss.qualcomm.com>
Reviewed-by: Marco Liebel <marco.liebel@oss.qualcomm.com>
Signed-off-by: Taylor Simpson <ltaylorsimpson@gmail.com>
Signed-off-by: Brian Cain <brian.cain@oss.qualcomm.com>

target/hexagon/decode.c

@@ -691,55 +691,6 @@ bool opcode_supported(uint16_t opcode, const HexagonCPUDef *hex_def)
     return true;
 }
 
-/*
- * Check for GPR write conflicts in the packet.
- * A conflict exists when a register is written by more than one instruction
- * and at least one of those writes is unconditional.
- *
- * TODO: handle the more general case of any
- * packet w/multiple-register-write operands.
- */
-static bool pkt_has_write_conflict(Packet *pkt)
-{
-    DECLARE_BITMAP(all_dest_gprs, 32) = { 0 };
-    DECLARE_BITMAP(wreg_mult_gprs, 32) = { 0 };
-    DECLARE_BITMAP(uncond_wreg_gprs, 32) = { 0 };
-    DECLARE_BITMAP(conflict, 32);
-
-    for (int i = 0; i < pkt->num_insns; i++) {
-        Insn *insn = &pkt->insn[i];
-        int dest = insn->dest_idx;
-
-        if (dest < 0 || !insn->dest_is_gpr) {
-            continue;
-        }
-
-        int rnum = insn->regno[dest];
-        bool is_uncond = !GET_ATTRIB(insn->opcode, A_CONDEXEC);
-
-        if (test_bit(rnum, all_dest_gprs)) {
-            set_bit(rnum, wreg_mult_gprs);
-        }
-        set_bit(rnum, all_dest_gprs);
-        if (is_uncond) {
-            set_bit(rnum, uncond_wreg_gprs);
-        }
-
-        if (insn->dest_is_pair) {
-            if (test_bit(rnum + 1, all_dest_gprs)) {
-                set_bit(rnum + 1, wreg_mult_gprs);
-            }
-            set_bit(rnum + 1, all_dest_gprs);
-            if (is_uncond) {
-                set_bit(rnum + 1, uncond_wreg_gprs);
-            }
-        }
-    }
-
-    bitmap_and(conflict, wreg_mult_gprs, uncond_wreg_gprs, 32);
-    return !bitmap_empty(conflict, 32);
-}
-
 /*
  * decode_packet
  * Decodes packet with given words
@@ -759,10 +710,6 @@ int decode_packet(DisasContext *ctx, int max_words, const uint32_t *words,
 
     /* Initialize */
     memset(pkt, 0, sizeof(*pkt));
-    for (i = 0; i < INSTRUCTIONS_MAX; i++) {
-        pkt->insn[i].dest_idx = -1;
-        pkt->insn[i].new_read_idx = -1;
-    }
     /* Try to build packet */
     while (!end_of_packet && (words_read < max_words)) {
         Insn *insn = &pkt->insn[num_insns];
@@ -837,7 +784,6 @@ int decode_packet(DisasContext *ctx, int max_words, const uint32_t *words,
             /* Invalid packet */
             return 0;
         }
-        pkt->pkt_has_write_conflict = pkt_has_write_conflict(pkt);
     }
     decode_fill_newvalue_regno(pkt);
 

target/hexagon/gen_trans_funcs.py

@@ -91,8 +91,6 @@ def gen_trans_funcs(f):
         new_read_idx = -1
         dest_idx = -1
         dest_idx_reg_id = None
-        dest_is_pair = "false"
-        dest_is_gpr = "false"
         has_pred_dest = "false"
         for regno, (reg_type, reg_id, *_) in enumerate(regs):
             reg = hex_common.get_register(tag, reg_type, reg_id)
@@ -106,12 +104,6 @@ def gen_trans_funcs(f):
                 if dest_idx_reg_id is None or reg_id < dest_idx_reg_id:
                     dest_idx = regno
                     dest_idx_reg_id = reg_id
-                    dest_is_pair = ("true"
-                                    if isinstance(reg, hex_common.Pair)
-                                    else "false")
-                    dest_is_gpr = ("true"
-                                   if reg_type == "R"
-                                   else "false")
             if reg_type == "P" and reg.is_written() and not reg.is_read():
                 has_pred_dest = "true"
 
@@ -137,8 +129,6 @@ def gen_trans_funcs(f):
         f.write(code_fmt(f"""\
             insn->new_read_idx = {new_read_idx};
             insn->dest_idx = {dest_idx};
-            insn->dest_is_pair = {dest_is_pair};
-            insn->dest_is_gpr = {dest_is_gpr};
             insn->has_pred_dest = {has_pred_dest};
         """))
         f.write(textwrap.dedent(f"""\

target/hexagon/insn.h

@@ -41,8 +41,6 @@ struct Instruction {
     uint32_t new_value_producer_slot:4;
     int32_t new_read_idx;
     int32_t dest_idx;
-    bool dest_is_pair;
-    bool dest_is_gpr;
     bool has_pred_dest;
 
     bool part1;              /*
@@ -74,8 +72,6 @@ struct Packet {
     bool pkt_has_hvx;
     Insn *vhist_insn;
 
-    bool pkt_has_write_conflict;
-
     Insn insn[INSTRUCTIONS_MAX];
 };
 

target/hexagon/translate.c

@@ -1253,12 +1253,6 @@ static void decode_and_translate_packet(CPUHexagonState *env, DisasContext *ctx)
         clear_pkt_ctx(ctx);
         analyze_packet(ctx);
 
-        /*
-         * Check that the new method is a superset of the old methond
-         * Remove in a later patch
-         */
-        g_assert(!ctx->pkt.pkt_has_write_conflict ||
-                 pkt_has_write_conflict(ctx));
         if (pkt_has_write_conflict(ctx)) {
             gen_exception_decode_fail(ctx, words_read,
                                       HEX_CAUSE_REG_WRITE_CONFLICT);