tcg: Optimize mulu2
Like add2, do operand ordering, constant folding, and dead operand
elimination. The latter happens about 15% of all mulu2 during an
x86_64 bios boot.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/tcg/optimize.c b/tcg/optimize.c
index 05891ef..a06c8eb 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -543,6 +543,9 @@
swap_commutative(args[0], &args[2], &args[4]);
swap_commutative(args[1], &args[3], &args[5]);
break;
+ case INDEX_op_mulu2_i32:
+ swap_commutative(args[0], &args[2], &args[3]);
+ break;
case INDEX_op_brcond2_i32:
if (swap_commutative2(&args[0], &args[2])) {
args[4] = tcg_swap_cond(args[4]);
@@ -831,6 +834,29 @@
}
goto do_default;
+ case INDEX_op_mulu2_i32:
+ if (temps[args[2]].state == TCG_TEMP_CONST
+ && temps[args[3]].state == TCG_TEMP_CONST) {
+ uint32_t a = temps[args[2]].val;
+ uint32_t b = temps[args[3]].val;
+ uint64_t r = (uint64_t)a * b;
+ TCGArg rl, rh;
+
+ /* We emit the extra nop when we emit the mulu2. */
+ assert(gen_opc_buf[op_index + 1] == INDEX_op_nop);
+
+ rl = args[0];
+ rh = args[1];
+ gen_opc_buf[op_index] = INDEX_op_movi_i32;
+ gen_opc_buf[++op_index] = INDEX_op_movi_i32;
+ tcg_opt_gen_movi(&gen_args[0], rl, (uint32_t)r);
+ tcg_opt_gen_movi(&gen_args[2], rh, (uint32_t)(r >> 32));
+ gen_args += 4;
+ args += 4;
+ break;
+ }
+ goto do_default;
+
case INDEX_op_brcond2_i32:
tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]);
if (tmp != 2) {