From: Takayuki 'January June' Suwa <jjsuwa_sys3175@yahoo.co.jp>
Date: Thu, 12 Jan 2023 04:26:42 +0000 (+0900)
Subject: xtensa: Optimize ctzsi2 and ffssi2 a bit
X-Git-Tag: basepoints/gcc-14~2086
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=117be79bd84ed21b47588d0cd86d72d5d1757cae;p=thirdparty%2Fgcc.git

xtensa: Optimize ctzsi2 and ffssi2 a bit

This patch saves one byte when the Code Density Option is enabled,

gcc/ChangeLog:

	* config/xtensa/xtensa.md (ctzsi2, ffssi2):
	Rearrange the emitting codes.
---

diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index b4989832169c..764da63f91cb 100644
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -477,8 +477,8 @@
   emit_insn (gen_negsi2 (temp, operands[1]));
   emit_insn (gen_andsi3 (temp, temp, operands[1]));
   emit_insn (gen_clzsi2 (temp, temp));
-  emit_insn (gen_negsi2 (temp, temp));
-  emit_insn (gen_addsi3 (operands[0], temp, GEN_INT (31)));
+  emit_move_insn (operands[0], GEN_INT (31));
+  emit_insn (gen_subsi3 (operands[0], operands[0], temp));
   DONE;
 })
 
@@ -491,8 +491,8 @@
   emit_insn (gen_negsi2 (temp, operands[1]));
   emit_insn (gen_andsi3 (temp, temp, operands[1]));
   emit_insn (gen_clzsi2 (temp, temp));
-  emit_insn (gen_negsi2 (temp, temp));
-  emit_insn (gen_addsi3 (operands[0], temp, GEN_INT (32)));
+  emit_move_insn (operands[0], GEN_INT (32));
+  emit_insn (gen_subsi3 (operands[0], operands[0], temp));
   DONE;
 })