Use tcg_op_imm_match to choose between expanding with AND+SHL vs SHL+SHR.
Suggested-by: Paolo Bonzini <[email protected]>
Signed-off-by: Richard Henderson <[email protected]>
---
tcg/optimize.c | 36 ++++++++++++++++++++++++++++++------
1 file changed, 30 insertions(+), 6 deletions(-)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index 59761c2c84..b1abec69a5 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -1743,14 +1743,38 @@ static bool fold_deposit(OptContext *ctx, TCGOp *op)
goto done;
}
- /* Lower invalid deposit into zero as AND + SHL. */
+ /* Lower invalid deposit into zero as AND + SHL or SHL + SHR. */
if (!valid) {
- op2 = opt_insert_before(ctx, op, INDEX_op_and, 3);
- op2->args[0] = ret;
- op2->args[1] = arg2;
- op2->args[2] = arg_new_constant(ctx, len_mask);
- fold_and(ctx, op2);
+ if (TCG_TARGET_extract_valid(ctx->type, 0, len)) {
+ /* EXTRACT (at 0) + SHL */
+ op2 = opt_insert_before(ctx, op, INDEX_op_extract, 4);
+ op2->args[0] = ret;
+ op2->args[1] = arg2;
+ op2->args[2] = 0;
+ op2->args[3] = len;
+ } else if (tcg_op_imm_match(INDEX_op_and, ctx->type, len_mask)) {
+ /* AND + SHL */
+ op2 = opt_insert_before(ctx, op, INDEX_op_and, 3);
+ op2->args[0] = ret;
+ op2->args[1] = arg2;
+ op2->args[2] = arg_new_constant(ctx, len_mask);
+ } else {
+ /* SHL + SHR */
+ int shl = width - len;
+ int shr = width - len - ofs;
+ op2 = opt_insert_before(ctx, op, INDEX_op_shl, 3);
+ op2->args[0] = ret;
+ op2->args[1] = arg2;
+ op2->args[2] = arg_new_constant(ctx, shl);
+
+ op->opc = INDEX_op_shr;
+ op->args[1] = ret;
+ op->args[2] = arg_new_constant(ctx, shr);
+ goto done;
+ }
+
+ /* Finish the (EXTRACT|AND) + SHL cases. */
op->opc = INDEX_op_shl;
op->args[1] = ret;
op->args[2] = arg_new_constant(ctx, ofs);
--
2.43.0
