diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index a01bfad773..9fc5592f5d 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -1091,7 +1091,7 @@ static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
 {
     /* This function is only used for passing structs by reference. */
     tcg_debug_assert(imm == (int32_t)imm);
-    tcg_out_modrm_offset(s, OPC_LEA, rd, rs, imm);
+    tcg_out_modrm_offset(s, OPC_LEA | P_REXW, rd, rs, imm);
 }
 
 static inline void tcg_out_pushi(TCGContext *s, tcg_target_long val)