Fixed left shift. Will promote the left side of a left shift

if a) left shifting more than size of operand or b) when assigned
to something size > size of left side

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@1997 4a8a32a2-be11-0410-ad9d-d568d2c75423

diff --git a/src/SDCCast.c b/src/SDCCast.c
index e66872b303c1060f6789a0642a2152b891ab2994..61c5655bf6be7dfee42c8ba9522d618a664c23b9 100644 (file)
--- a/src/SDCCast.c
+++ b/src/SDCCast.c
@@ -1958,6 +1958,22 @@ decorateType (ast * tree)
       tree->left = dtl;
     if (dtr != tree->right)
       tree->right = dtr;
+
+    /* special case for left shift operation : cast up right->left if type of left
+       has greater size than right */
+    if (tree->left && tree->right && tree->right->opval.op == LEFT_OP) {
+       int lsize = getSize(LTYPE(tree));
+       int rsize = getSize(RTYPE(tree));
+
+       if (lsize > rsize) {
+           tree->right->decorated = 0;
+           tree->right->left = newNode( CAST, (lsize == 2 ? 
+                                              newAst_LINK(newIntLink()) : 
+                                              newAst_LINK(newLongLink())),
+                                       tree->right->left);
+           tree->right = decorateType(tree->right);
+       }
+    }
   }
 
   /* depending on type of operator do */
@@ -2671,6 +2687,7 @@ decorateType (ast * tree)
                                   tree->opval.val->type);
          return tree;
        }
+#if 0
       /* a left shift must be done with at least 16bits */
       if ((tree->opval.op==LEFT_OP) && (getSize(LTYPE(tree))<2)) {
        // insert a cast
@@ -2685,19 +2702,31 @@ decorateType (ast * tree)
          SPEC_NOUN(tree->left->opval.val->type)=V_INT;
        }
       }
+#endif
       /* if only the right side is a literal & we are
          shifting more than size of the left operand then zero */
       if (IS_LITERAL (RTYPE (tree)) &&
          ((unsigned) floatFromVal (valFromType (RETYPE (tree)))) >=
          (getSize (LTYPE (tree)) * 8))
        {
-         werror (W_SHIFT_CHANGED,
-                 (tree->opval.op == LEFT_OP ? "left" : "right"));
-         tree->type = EX_VALUE;
-         tree->left = tree->right = NULL;
-         tree->opval.val = constVal ("0");
-         TETYPE (tree) = TTYPE (tree) = tree->opval.val->type;
-         return tree;
+           /* if left shift then cast up */
+           if (tree->opval.op==LEFT_OP) {
+               int size = getSize(LTYPE(tree));
+               tree->left = 
+                   decorateType (newNode (CAST,
+                                          (size == 1 ? newAst_LINK(newIntLink()) : 
+                                           (size == 2 ? newAst_LINK(newLongLink()) : 
+                                            newAst_LINK(newIntLink()))),
+                                          tree->left));
+           } else {
+               werror (W_SHIFT_CHANGED,
+                       (tree->opval.op == LEFT_OP ? "left" : "right"));
+               tree->type = EX_VALUE;
+               tree->left = tree->right = NULL;
+               tree->opval.val = constVal ("0");
+               TETYPE (tree) = TTYPE (tree) = tree->opval.val->type;
+               return tree;
+           }
        }
       LRVAL (tree) = RRVAL (tree) = 1;
       if (IS_LITERAL (LTYPE (tree)) && !IS_LITERAL (RTYPE (tree)))