Gcc indeed doesn't seem to complain, however, there was a reason why I remembered there was a warning, and it's a different compiler. Borland C 3.1 has such a warning.

Update: I recreated a variant of the screenshot I've linked to and made a text export. Non-ascii characters are wrong so the image I linked to is still better, but I copy the text version here in case you can't view the image and because it's not hosted on perlmonks.

  =  File  Edit  Search  Run  Compile  Debug  Project  Options    Wind
+ow  Help 
+--------------------------------- \TEMP\A.C -------------------------
+---2-----+ 
|#include <stdio.h>                                                   
+         | 
|int                                       +-[_]---------- About -----
+---------+ 
|main(void) {                              |                          
+         | 
|    return(1 << 5 >> 1);                  |            Borland C++   
+         | 
|}                                         |                          
+         | 
|                                          |            Version 3.1   
+         | 
|                                          |                          
+         | 
|                                          |    Copyright (c) 1990, 19
+92 by    | 
|                                          |                          
+         | 
|                                          |    Borland International,
+ Inc.    | 
|                                          |                          
+         | 
|                                          |                OK   _    
+         | 
|                                          |              ________    
+         | 
|                                          +--------------------------
+---------+ 
+------- 4:21 --------------------------------------------------------
+---------+ 
+-[_]------------------------------ Message --------------------------
+---3-[o]-+ 
| Compiling ..\TEMP\A.C:                                              
+         ^ 
|*Warning ..\TEMP\A.C 4: Ambiguous operators need parentheses         
+         _ 
| Linking A.EXE:                                                      
+         _ 
|                                                                     
+         _ 
|                                                                     
+         v 
+-<___________________________________________________________________
+_______>-+ 
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