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tcg/optimize: simplify shift/rot r, 0, a => movi r, 0 cases

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shift/rot r, 0, a is equivalent to movi r, 0.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Aurelien Jarno 2012-09-06 16:47:14 +02:00
parent 61251c0c79
commit 01ee5282ea
1 changed files with 20 additions and 0 deletions
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20
tcg/optimize.c
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@ -322,6 +322,26 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
break;
}
/* Simplify expressions for "shift/rot r, 0, a => movi r, 0" */
switch (op) {
CASE_OP_32_64(shl):
CASE_OP_32_64(shr):
CASE_OP_32_64(sar):
CASE_OP_32_64(rotl):
CASE_OP_32_64(rotr):
if (temps[args[1]].state == TCG_TEMP_CONST
&& temps[args[1]].val == 0) {
gen_opc_buf[op_index] = op_to_movi(op);
tcg_opt_gen_movi(gen_args, args[0], 0, nb_temps, nb_globals);
args += 3;
gen_args += 2;
continue;
}
break;
default:
break;
}
/* Simplify expression for "op r, a, 0 => mov r, a" cases */
switch (op) {
CASE_OP_32_64(add):