Re: [PATCH v3 4/5] xtensa: Add setmemsi insn pattern

[Takayuki 'January June' Suwa <jjsuwa_sys3175@yahoo.co.jp>]

On 2022/05/27 12:00, Takayuki 'January June' Suwa via Gcc-patches wrote:
> On 2022/05/27 1:57, Max Filippov wrote:
>> is that something that can be addressed in this patch?
> 
> seems hard to resolve, because the RTL-generation pass passes only 68 
> bytes in that case:

the culprit is here, but i don't know whether it is known regression or not.

diff --git a/gcc/expr.cc b/gcc/expr.cc
index 7197996cec7..be100dd9946 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -6043,13 +6043,19 @@ store_expr (tree exp, rtx target, int call_param_p,
        if (!can_store_by_pieces (str_copy_len, string_cst_read_str,
  				(void *) str, MEM_ALIGN (target), false))
  	goto normal_expr;
-
-      dest_mem = store_by_pieces (target, str_copy_len, 
string_cst_read_str,
-				  (void *) str, MEM_ALIGN (target), false,
-				  RETURN_END);
-      clear_storage (adjust_address_1 (dest_mem, BLKmode, 0, 1, 1, 0,
-				       exp_len - str_copy_len),
-		     GEN_INT (exp_len - str_copy_len), BLOCK_OP_NORMAL);
+      if (TREE_STRING_LENGTH (str) == 1 && *TREE_STRING_POINTER (str) == 0)
+	clear_storage (adjust_address_1 (target, BLKmode, 0, 1, 1, 0,
+					 exp_len),
+		       GEN_INT (exp_len), BLOCK_OP_NORMAL);
+      else
+	{
+	  dest_mem = store_by_pieces (target, str_copy_len, string_cst_read_str,
+				      (void *) str, MEM_ALIGN (target), false,
+				      RETURN_END);
+	  clear_storage (adjust_address_1 (dest_mem, BLKmode, 0, 1, 1, 0,
+					   exp_len - str_copy_len),
+			 GEN_INT (exp_len - str_copy_len), BLOCK_OP_NORMAL);
+	}
        return NULL_RTX;
      }
    else