@@ -2251,6 +2251,19 @@ static bool fold_tcg_st_memcopy(OptContext *ctx, TCGOp *op)
src = arg_temp(op->args[0]);
ofs = op->args[2];
type = ctx->type;
+
+ /*
+ * Eliminate duplicate stores of a constant.
+ * This happens frequently when the target ISA zero-extends.
+ */
+ if (ts_is_const(src)) {
+ TCGTemp *prev = find_mem_copy_for(ctx, type, ofs);
+ if (src == prev) {
+ tcg_op_remove(ctx->tcg, op);
+ return true;
+ }
+ }
+
last = ofs + tcg_type_size(type) - 1;
remove_mem_copy_in(ctx, ofs, last);
record_mem_copy(ctx, type, src, ofs, last);
Notice when a constant is stored to the same location twice. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- tcg/optimize.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)