From e884e045de7809f8d826dfb7703371a7b7536a47 Mon Sep 17 00:00:00 2001
From: Dmitry Stogov <dmitry@zend.com>
Date: Fri, 16 Dec 2022 13:38:58 +0300
Subject: [PATCH] Avoid zero extension to the same register

---
 ir_x86.dasc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ir_x86.dasc b/ir_x86.dasc
index b001a1f..14c7bb1 100644
--- a/ir_x86.dasc
+++ b/ir_x86.dasc
@@ -4308,7 +4308,10 @@ static void ir_emit_zext(ir_ctx *ctx, ir_ref def, ir_insn *insn)
 			IR_ASSERT(ir_type_size[dst_type] == 8);
 			IR_ASSERT(sizeof(void*) == 8);
 |.if X64
-			|	mov Rd(def_reg), Rd(op1_reg)
+			/* Avoid zero extension to the same register. This may be not always safe ??? */
+			if (op1_reg != def_reg) {
+				|	mov Rd(def_reg), Rd(op1_reg)
+			}
 |.endif
 		}
 	} else if (IR_IS_CONST_REF(insn->op1)) {