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Backported from mainline
authorjakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4>
Wed, 7 May 2014 16:05:38 +0000 (16:05 +0000)
committerjakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4>
Wed, 7 May 2014 16:05:38 +0000 (16:05 +0000)
2013-09-30  Jakub Jelinek  <jakub@redhat.com>

PR middle-end/58564
* fold-const.c (fold_ternary_loc): For A < 0 : <sign bit of A> : 0
optimization, punt if sign_bit_p looked through any zero extension.

* gcc.c-torture/execute/pr58564.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_7-branch@210174 138bc75d-0d04-0410-961f-82ee72b054a4

gcc/ChangeLog
gcc/fold-const.c
gcc/testsuite/ChangeLog
gcc/testsuite/gcc.c-torture/execute/pr58564.c [new file with mode: 0644]

index 139a579..940ed0f 100644 (file)
@@ -1,6 +1,12 @@
 2014-05-07  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline
+       2013-09-30  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/58564
+       * fold-const.c (fold_ternary_loc): For A < 0 : <sign bit of A> : 0
+       optimization, punt if sign_bit_p looked through any zero extension.
+
        2013-09-10  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/58365
index 804a05f..d83f084 100644 (file)
@@ -13849,14 +13849,29 @@ fold_ternary_loc (location_t loc, enum tree_code code, tree type,
          && integer_zerop (op2)
          && (tem = sign_bit_p (TREE_OPERAND (arg0, 0), arg1)))
        {
+         /* sign_bit_p looks through both zero and sign extensions,
+            but for this optimization only sign extensions are
+            usable.  */
+         tree tem2 = TREE_OPERAND (arg0, 0);
+         while (tem != tem2)
+           {
+             if (TREE_CODE (tem2) != NOP_EXPR
+                 || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (tem2, 0))))
+               {
+                 tem = NULL_TREE;
+                 break;
+               }
+             tem2 = TREE_OPERAND (tem2, 0);
+           }
          /* sign_bit_p only checks ARG1 bits within A's precision.
             If <sign bit of A> has wider type than A, bits outside
             of A's precision in <sign bit of A> need to be checked.
             If they are all 0, this optimization needs to be done
             in unsigned A's type, if they are all 1 in signed A's type,
             otherwise this can't be done.  */
-         if (TYPE_PRECISION (TREE_TYPE (tem))
-             < TYPE_PRECISION (TREE_TYPE (arg1))
+         if (tem
+             && TYPE_PRECISION (TREE_TYPE (tem))
+                < TYPE_PRECISION (TREE_TYPE (arg1))
              && TYPE_PRECISION (TREE_TYPE (tem))
                 < TYPE_PRECISION (type))
            {
index 3623178..b28b8ad 100644 (file)
@@ -1,6 +1,11 @@
 2014-05-07  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline
+       2013-09-30  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/58564
+       * gcc.c-torture/execute/pr58564.c: New test.
+
        2013-09-10  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/58365
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr58564.c b/gcc/testsuite/gcc.c-torture/execute/pr58564.c
new file mode 100644 (file)
index 0000000..967ee95
--- /dev/null
@@ -0,0 +1,14 @@
+/* PR middle-end/58564 */
+
+extern void abort (void);
+int a, b;
+short *c, **d = &c;
+
+int
+main ()
+{
+  b = (0, 0 > ((&c == d) & (1 && (a ^ 1)))) | 0U;
+  if (b != 0)
+    abort ();
+  return 0;
+}