X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/5a35a6cb7199aa58dc0b0cc6386872f5da18e1fe..090c5ebfa813d77aa5f57e6e249ac1cfbc1d36ad:/src/bison.s1

diff --git a/src/bison.s1 b/src/bison.s1
index bc656245..aee33e27 100644
--- a/src/bison.s1
+++ b/src/bison.s1
@@ -558,10 +558,16 @@ yydefault:
 yyreduce:
   /* yyn is the number of a rule to reduce with.  */
   yylen = yyr2[yyn];
-  /* Implement default value of the action:
-     `{dollar}{dollar} = {dollar}1'. */
-  if (yylen > 0)
-      yyval = yyvsp[1-yylen];
+
+  /* If YYLEN is nonzero, implement the default value of the action:
+     `{dollar}{dollar} = {dollar}1'.
+
+     Otherwise, the following line sets YYVAL to the semantic value of
+     the lookahead token.  This behavior is undocumented and Bison
+     users should not rely upon it.  Assigning to YYVAL
+     unconditionally makes the parser a bit smaller, and it avoids a
+     GCC warning that YYVAL may be used uninitialized.  */
+  yyval = yyvsp[1-yylen];
 #ifdef YYLSP_NEEDED
   /* Implement default location.  If the rhs is empty, extend YYLOC to
      YYLLOC, which corresponds to the current token, otherwise