Re: [Tinycc-devel] tcc 0.9.23 shift generation bug

[Felix Nawothnig]

Michael Somos wrote:
> There is a bug in shift generation. Notice the "1UL". If it is just "1"
> instead, the code is "sar" as expected. Here is script showing difference :
> [...]
> int i;
> int main(void){ return i >> 1UL ; }

A quick fix:

--- tcc.c       17 Apr 2005 13:15:54 -0000      1.170
+++ tcc.c       20 Jun 2005 12:40:18 -0000
@@ -5600,7 +5600,7 @@
         /* XXX: currently, some unsigned operations are explicit, so
            we modify them here */
         if (t & VT_UNSIGNED) {
-            if (op == TOK_SAR)
+            if (op == TOK_SAR && (t1 & VT_UNSIGNED))
                 op = TOK_SHR;
             else if (op == '/')
                 op = TOK_UDIV;


Nevertheless you should keep in mind that for both C89 and C99 the 
result of a signed right shift is undefined (which was a silly decision 
IMO) so the current behaviour is probably not stricly wrong (although 
most likely not the indented one).

Felix