Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20231026013945.1152174-3-richard.henderson@linaro.org>
---
tcg/optimize.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index d8e437c826..468f827399 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -2166,7 +2166,19 @@ static bool fold_sub_vec(OptContext *ctx, TCGOp *op)
static bool fold_sub(OptContext *ctx, TCGOp *op)
{
- return fold_const2(ctx, op) || fold_sub_vec(ctx, op);
+ if (fold_const2(ctx, op) || fold_sub_vec(ctx, op)) {
+ return true;
+ }
+
+ /* Fold sub r,x,i to add r,x,-i */
+ if (arg_is_const(op->args[2])) {
+ uint64_t val = arg_info(op->args[2])->val;
+
+ op->opc = (ctx->type == TCG_TYPE_I32
+ ? INDEX_op_add_i32 : INDEX_op_add_i64);
+ op->args[2] = arg_new_constant(ctx, -val);
+ }
+ return false;
}
static bool fold_sub2(OptContext *ctx, TCGOp *op)
--
2.34.1