tcg: Add tcg_reg_alloc_dup2

There are several ways we can expand a vector dup of a 64-bit
element on a 32-bit host.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/tcg.c

@@ -4084,6 +4084,98 @@ static void tcg_reg_alloc_op(TCGContext *s, const TCGOp *op)
     }
 }
 
+static bool tcg_reg_alloc_dup2(TCGContext *s, const TCGOp *op)
+{
+    const TCGLifeData arg_life = op->life;
+    TCGTemp *ots, *itsl, *itsh;
+    TCGType vtype = TCGOP_VECL(op) + TCG_TYPE_V64;
+
+    /* This opcode is only valid for 32-bit hosts, for 64-bit elements. */
+    tcg_debug_assert(TCG_TARGET_REG_BITS == 32);
+    tcg_debug_assert(TCGOP_VECE(op) == MO_64);
+
+    ots = arg_temp(op->args[0]);
+    itsl = arg_temp(op->args[1]);
+    itsh = arg_temp(op->args[2]);
+
+    /* ENV should not be modified.  */
+    tcg_debug_assert(!temp_readonly(ots));
+
+    /* Allocate the output register now.  */
+    if (ots->val_type != TEMP_VAL_REG) {
+        TCGRegSet allocated_regs = s->reserved_regs;
+        TCGRegSet dup_out_regs =
+            tcg_op_defs[INDEX_op_dup_vec].args_ct[0].regs;
+
+        /* Make sure to not spill the input registers. */
+        if (!IS_DEAD_ARG(1) && itsl->val_type == TEMP_VAL_REG) {
+            tcg_regset_set_reg(allocated_regs, itsl->reg);
+        }
+        if (!IS_DEAD_ARG(2) && itsh->val_type == TEMP_VAL_REG) {
+            tcg_regset_set_reg(allocated_regs, itsh->reg);
+        }
+
+        ots->reg = tcg_reg_alloc(s, dup_out_regs, allocated_regs,
+                                 op->output_pref[0], ots->indirect_base);
+        ots->val_type = TEMP_VAL_REG;
+        ots->mem_coherent = 0;
+        s->reg_to_temp[ots->reg] = ots;
+    }
+
+    /* Promote dup2 of immediates to dupi_vec. */
+    if (itsl->val_type == TEMP_VAL_CONST && itsh->val_type == TEMP_VAL_CONST) {
+        uint64_t val = deposit64(itsl->val, 32, 32, itsh->val);
+        MemOp vece = MO_64;
+
+        if (val == dup_const(MO_8, val)) {
+            vece = MO_8;
+        } else if (val == dup_const(MO_16, val)) {
+            vece = MO_16;
+        } else if (val == dup_const(MO_32, val)) {
+            vece = MO_32;
+        }
+
+        tcg_out_dupi_vec(s, vtype, vece, ots->reg, val);
+        goto done;
+    }
+
+    /* If the two inputs form one 64-bit value, try dupm_vec. */
+    if (itsl + 1 == itsh && itsl->base_type == TCG_TYPE_I64) {
+        if (!itsl->mem_coherent) {
+            temp_sync(s, itsl, s->reserved_regs, 0, 0);
+        }
+        if (!itsh->mem_coherent) {
+            temp_sync(s, itsh, s->reserved_regs, 0, 0);
+        }
+#ifdef HOST_WORDS_BIGENDIAN
+        TCGTemp *its = itsh;
+#else
+        TCGTemp *its = itsl;
+#endif
+        if (tcg_out_dupm_vec(s, vtype, MO_64, ots->reg,
+                             its->mem_base->reg, its->mem_offset)) {
+            goto done;
+        }
+    }
+
+    /* Fall back to generic expansion. */
+    return false;
+
+ done:
+    if (IS_DEAD_ARG(1)) {
+        temp_dead(s, itsl);
+    }
+    if (IS_DEAD_ARG(2)) {
+        temp_dead(s, itsh);
+    }
+    if (NEED_SYNC_ARG(0)) {
+        temp_sync(s, ots, s->reserved_regs, 0, IS_DEAD_ARG(0));
+    } else if (IS_DEAD_ARG(0)) {
+        temp_dead(s, ots);
+    }
+    return true;
+}
+
 #ifdef TCG_TARGET_STACK_GROWSUP
 #define STACK_DIR(x) (-(x))
 #else
@@ -4501,6 +4593,11 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
         case INDEX_op_call:
             tcg_reg_alloc_call(s, op);
             break;
+        case INDEX_op_dup2_vec:
+            if (tcg_reg_alloc_dup2(s, op)) {
+                break;
+            }
+            /* fall through */
         default:
             /* Sanity check that we've not introduced any unhandled opcodes. */
             tcg_debug_assert(tcg_op_supported(opc));