[PATCH v2 18/35] tcg/wasm: Add neg/ctpop instructions

[Kohei Tokunaga <ktokunaga.mail@gmail.com>]

The neg/ctpop operations are implemented using the corresponding
instructions in Wasm. TCI instructions are also generated in the same way as
the original TCI backend.

The Wasm backend implements only TCG_TARGET_REG_BITS=64 so the ctpop
instruction is generated only for 64bit operations, as declared in
cset_ctpop. Therefore, this commit adds only the 64bit version of ctpop
implementation.

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
---
 tcg/wasm.c                |  4 ++++
 tcg/wasm/tcg-target.c.inc | 44 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

V2:
- This commit generates both Wasm and TCI instrucitons.
- Removed the not operation to rely on default expansion.
- Fixed the neg implementation to "ret = 0 - arg"

diff --git a/tcg/wasm.c b/tcg/wasm.c
index 8c8dcb81c7..a5e72d8fe5 100644
--- a/tcg/wasm.c
+++ b/tcg/wasm.c
@@ -359,6 +359,10 @@ static uintptr_t tcg_qemu_tb_exec_tci(CPUArchState *env, const void *v_tb_ptr)
             tci_args_rrr(insn, &r0, &r1, &r2);
             regs[r0] = (uint32_t)regs[r1] % (uint32_t)regs[r2];
             break;
+        case INDEX_op_ctpop:
+            tci_args_rr(insn, &r0, &r1);
+            regs[r0] = ctpop64(regs[r1]);
+            break;
         default:
             g_assert_not_reached();
         }
diff --git a/tcg/wasm/tcg-target.c.inc b/tcg/wasm/tcg-target.c.inc
index 38459a60d6..27f3a7414b 100644
--- a/tcg/wasm/tcg-target.c.inc
+++ b/tcg/wasm/tcg-target.c.inc
@@ -188,6 +188,7 @@ typedef enum {
     OPC_I32_SHR_S = 0x75,
     OPC_I32_SHR_U = 0x76,
 
+    OPC_I64_POPCNT = 0x7b,
     OPC_I64_ADD = 0x7c,
     OPC_I64_SUB = 0x7d,
     OPC_I64_MUL = 0x7e,
@@ -547,6 +548,21 @@ static void tcg_wasm_out_movi(TCGContext *s, TCGType type,
    tcg_wasm_out_op_idx(s, OPC_GLOBAL_SET, REG_IDX(ret));
 }
 
+static void tcg_wasm_out_neg(TCGContext *s, TCGReg ret, TCGReg arg)
+{
+    tcg_wasm_out_op_const(s, OPC_I64_CONST, 0);
+    tcg_wasm_out_op_idx(s, OPC_GLOBAL_GET, REG_IDX(arg));
+    tcg_wasm_out_op(s, OPC_I64_SUB);
+    tcg_wasm_out_op_idx(s, OPC_GLOBAL_SET, REG_IDX(ret));
+}
+
+static void tcg_wasm_out_ctpop64(TCGContext *s, TCGReg ret, TCGReg arg)
+{
+    tcg_wasm_out_op_idx(s, OPC_GLOBAL_GET, REG_IDX(arg));
+    tcg_wasm_out_op(s, OPC_I64_POPCNT);
+    tcg_wasm_out_op_idx(s, OPC_GLOBAL_SET, REG_IDX(ret));
+}
+
 static void tcg_out_op_ri(TCGContext *s, TCGOpcode op, TCGReg r0, int32_t i1)
 {
     tcg_insn_unit_tci insn = 0;
@@ -1138,6 +1154,34 @@ static const TCGOutOpBinary outop_remu = {
     .out_rrr = tgen_remu,
 };
 
+static void tgen_neg(TCGContext *s, TCGType type, TCGReg a0, TCGReg a1)
+{
+    tcg_out_op_rr(s, INDEX_op_neg, a0, a1);
+    tcg_wasm_out_neg(s, a0, a1);
+}
+
+static const TCGOutOpUnary outop_neg = {
+    .base.static_constraint = C_O1_I1(r, r),
+    .out_rr = tgen_neg,
+};
+
+static void tgen_ctpop(TCGContext *s, TCGType type, TCGReg a0, TCGReg a1)
+{
+    tcg_out_op_rr(s, INDEX_op_ctpop, a0, a1);
+    tcg_wasm_out_ctpop64(s, a0, a1);
+}
+
+static TCGConstraintSetIndex cset_ctpop(TCGType type, unsigned flags)
+{
+    return type == TCG_TYPE_REG ? C_O1_I1(r, r) : C_NotImplemented;
+}
+
+static const TCGOutOpUnary outop_ctpop = {
+    .base.static_constraint = C_Dynamic,
+    .base.dynamic_constraint = cset_ctpop,
+    .out_rr = tgen_ctpop,
+};
+
 static void tcg_out_tb_start(TCGContext *s)
 {
     init_sub_buf();
-- 
2.43.0