[PULL v2 41/96] disas/riscv: Tidy disasm_inst main loop

From: Richard Henderson <[email protected]>

Unroll first iteration, so that always_true_p is not used,
Drop some local variables and use 'decoders' directly.

Reviewed-by: Alistair Francis <[email protected]>
Signed-off-by: Richard Henderson <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Alistair Francis <[email protected]>
---
 disas/riscv.c | 65 +++++++++++++++++++++++++--------------------------
 1 file changed, 32 insertions(+), 33 deletions(-)

diff --git a/disas/riscv.c b/disas/riscv.c
index 70ea41f125..9880b8de20 100644
--- a/disas/riscv.c
+++ b/disas/riscv.c
@@ -5419,41 +5419,40 @@ static GString *disasm_inst(rv_isa isa, uint64_t pc, rv_inst inst,
         .inst = inst,
         .cfg = cfg,
     };
-
-    static const struct {
-        bool (*guard_func)(const RISCVCPUConfig *);
-        const rv_opcode_data *opcode_data;
-        void (*decode_func)(rv_decode *, rv_isa);
-    } decoders[] = {
-        { always_true_p, rvi_opcode_data, decode_inst_opcode },
-        { has_xtheadba_p, xthead_opcode_data, decode_xtheadba },
-        { has_xtheadbb_p, xthead_opcode_data, decode_xtheadbb },
-        { has_xtheadbs_p, xthead_opcode_data, decode_xtheadbs },
-        { has_xtheadcmo_p, xthead_opcode_data, decode_xtheadcmo },
-        { has_xtheadcondmov_p, xthead_opcode_data, decode_xtheadcondmov },
-        { has_xtheadfmemidx_p, xthead_opcode_data, decode_xtheadfmemidx },
-        { has_xtheadfmv_p, xthead_opcode_data, decode_xtheadfmv },
-        { has_xtheadmac_p, xthead_opcode_data, decode_xtheadmac },
-        { has_xtheadmemidx_p, xthead_opcode_data, decode_xtheadmemidx },
-        { has_xtheadmempair_p, xthead_opcode_data, decode_xtheadmempair },
-        { has_xtheadsync_p, xthead_opcode_data, decode_xtheadsync },
-        { has_XVentanaCondOps_p, ventana_opcode_data, decode_xventanacondops },
-        { has_xlrbr_p, rv_xlrbr_opcode_data, decode_xlrbr },
-    };
-
     const rv_opcode_data *op;
 
-    for (size_t i = 0; i < ARRAY_SIZE(decoders); i++) {
-        bool (*guard_func)(const RISCVCPUConfig *) = decoders[i].guard_func;
-        const rv_opcode_data *opcode_data = decoders[i].opcode_data;
-        void (*decode_func)(rv_decode *, rv_isa) = decoders[i].decode_func;
-
-        /* always_true_p don't dereference cfg */
-        if (((i == 0) || cfg) && guard_func(cfg)) {
-            dec.opcode_data = opcode_data;
-            decode_func(&dec, isa);
-            if (dec.op != rv_op_illegal)
-                break;
+    dec.opcode_data = rvi_opcode_data;
+    decode_inst_opcode(&dec, isa);
+
+    if (dec.op == rv_op_illegal && cfg) {
+        static const struct {
+            bool (*guard_func)(const RISCVCPUConfig *);
+            const rv_opcode_data *opcode_data;
+            void (*decode_func)(rv_decode *, rv_isa);
+        } decoders[] = {
+            { has_xtheadba_p, xthead_opcode_data, decode_xtheadba },
+            { has_xtheadbb_p, xthead_opcode_data, decode_xtheadbb },
+            { has_xtheadbs_p, xthead_opcode_data, decode_xtheadbs },
+            { has_xtheadcmo_p, xthead_opcode_data, decode_xtheadcmo },
+            { has_xtheadcondmov_p, xthead_opcode_data, decode_xtheadcondmov },
+            { has_xtheadfmemidx_p, xthead_opcode_data, decode_xtheadfmemidx },
+            { has_xtheadfmv_p, xthead_opcode_data, decode_xtheadfmv },
+            { has_xtheadmac_p, xthead_opcode_data, decode_xtheadmac },
+            { has_xtheadmemidx_p, xthead_opcode_data, decode_xtheadmemidx },
+            { has_xtheadmempair_p, xthead_opcode_data, decode_xtheadmempair },
+            { has_xtheadsync_p, xthead_opcode_data, decode_xtheadsync },
+            { has_XVentanaCondOps_p, ventana_opcode_data, decode_xventanacondops },
+            { has_xlrbr_p, rv_xlrbr_opcode_data, decode_xlrbr },
+        };
+
+        for (size_t i = 0; i < ARRAY_SIZE(decoders); i++) {
+            if (decoders[i].guard_func(cfg)) {
+                dec.opcode_data = decoders[i].opcode_data;
+                decoders[i].decode_func(&dec, isa);
+                if (dec.op != rv_op_illegal) {
+                    break;
+                }
+            }
         }
     }
 
-- 
2.54.0