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tcg/optimize: Optimize bitsel_vec 

Fold matching true/false operands.
Fold true/false operands with 0/-1 to simpler logicals.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2024-09-06 22:30:01 -07:00
parent 1f106544fd
commit e58b977238
1 changed files with 58 additions and 0 deletions
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58
tcg/optimize.c
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@ -2737,6 +2737,61 @@ static bool fold_xor(OptContext *ctx, TCGOp *op)
return fold_masks(ctx, op);
}
static bool fold_bitsel_vec(OptContext *ctx, TCGOp *op)
{
/* If true and false values are the same, eliminate the cmp. */
if (args_are_copies(op->args[2], op->args[3])) {
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[2]);
}
if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])) {
uint64_t tv = arg_info(op->args[2])->val;
uint64_t fv = arg_info(op->args[3])->val;
if (tv == -1 && fv == 0) {
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
}
if (tv == 0 && fv == -1) {
if (TCG_TARGET_HAS_not_vec) {
op->opc = INDEX_op_not_vec;
return fold_not(ctx, op);
} else {
op->opc = INDEX_op_xor_vec;
op->args[2] = arg_new_constant(ctx, -1);
return fold_xor(ctx, op);
}
}
}
if (arg_is_const(op->args[2])) {
uint64_t tv = arg_info(op->args[2])->val;
if (tv == -1) {
op->opc = INDEX_op_or_vec;
op->args[2] = op->args[3];
return fold_or(ctx, op);
}
if (tv == 0 && TCG_TARGET_HAS_andc_vec) {
op->opc = INDEX_op_andc_vec;
op->args[2] = op->args[1];
op->args[1] = op->args[3];
return fold_andc(ctx, op);
}
}
if (arg_is_const(op->args[3])) {
uint64_t fv = arg_info(op->args[3])->val;
if (fv == 0) {
op->opc = INDEX_op_and_vec;
return fold_and(ctx, op);
}
if (fv == -1 && TCG_TARGET_HAS_orc_vec) {
op->opc = INDEX_op_orc_vec;
op->args[2] = op->args[1];
op->args[1] = op->args[3];
return fold_orc(ctx, op);
}
}
return false;
}
/* Propagate constants and copies, fold constant expressions. */
void tcg_optimize(TCGContext *s)
{
@ -2964,6 +3019,9 @@ void tcg_optimize(TCGContext *s)
case INDEX_op_cmpsel_vec:
done = fold_cmpsel_vec(&ctx, op);
break;
case INDEX_op_bitsel_vec:
done = fold_bitsel_vec(&ctx, op);
break;
CASE_OP_32_64(sextract):
done = fold_sextract(&ctx, op);
break;