backport: re PR middle-end/87248 (Bad code for masked operations involving signed...

	Backported from mainline
	2018-09-12  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/87248
	* fold-const.c (fold_ternary_loc) <case COND_EXPR>: Verify also that
	BIT_AND_EXPR's second operand is a power of two.  Formatting fix.

	* c-c++-common/torture/pr87248.c: New test.

From-SVN: r265111

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b3d278d37ae8a7227c84b12acb18f63e7317c0f1..a1b21e2a903a53b850f2ffcd91cd8cbb59dbb170 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,12 @@
 2018-10-12  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline
+       2018-09-12  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/87248
+       * fold-const.c (fold_ternary_loc) <case COND_EXPR>: Verify also that
+       BIT_AND_EXPR's second operand is a power of two.  Formatting fix.
+
        2018-08-27  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/87065

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index ba8dd4985544b6af7071d75404d1f2b0840aabca..38753293c317ccff427ebf3b4e64bd5f0edc3e6f 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -11589,10 +11589,16 @@ fold_ternary_loc (location_t loc, enum tree_code code, tree type,
          && integer_pow2p (arg1)
          && TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
          && operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
-                             arg1, OEP_ONLY_CONST))
+                             arg1, OEP_ONLY_CONST)
+         /* operand_equal_p compares just value, not precision, so e.g.
+            arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
+            second operand 32-bit -128, which is not a power of two (or vice
+            versa.  */
+         && integer_pow2p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)))
        return pedantic_non_lvalue_loc (loc,
-                                   fold_convert_loc (loc, type,
-                                                     TREE_OPERAND (arg0, 0)));
+                                       fold_convert_loc (loc, type,
+                                                         TREE_OPERAND (arg0,
+                                                                       0)));
 
       /* Disable the transformations below for vectors, since
         fold_binary_op_with_conditional_arg may undo them immediately,

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index db1689ab8b1b2541b21e2fcd8f55ffb06f65bf2f..d080b9b370ef5de246c2f6316f060e07d2644d77 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2018-10-12  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline
+       2018-09-12  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/87248
+       * c-c++-common/torture/pr87248.c: New test.
+
        2018-08-27  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/87065

diff --git a/gcc/testsuite/c-c++-common/torture/pr87248.c b/gcc/testsuite/c-c++-common/torture/pr87248.c
new file mode 100644 (file)
index 0000000..6f89bc9
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/torture/pr87248.c
@@ -0,0 +1,36 @@
+/* PR middle-end/87248 */
+/* { dg-do run } */
+
+void
+foo (signed char *p, int q)
+{
+  *p = q & (-__SCHAR_MAX__ - 1) ? (-__SCHAR_MAX__ - 1) : 0;
+}
+
+int
+bar (long long x)
+{
+  return x & (-__INT_MAX__ - 1) ? (-__INT_MAX__ - 1) : 0;
+}
+
+int
+main ()
+{
+#if __INT_MAX__ > 4 * __SCHAR_MAX__
+  signed char a[4];
+  foo (a, __SCHAR_MAX__ + 1U);
+  foo (a + 1, 2 * (__SCHAR_MAX__ + 1U));
+  foo (a + 2, -__INT_MAX__ - 1);
+  foo (a + 3, (__SCHAR_MAX__ + 1U) / 2);
+  if (a[0] != (-__SCHAR_MAX__ - 1) || a[1] != a[0] || a[2] != a[0] || a[3] != 0)
+    __builtin_abort ();
+#endif
+#if __LONG_LONG_MAX__ > 4 * __INT_MAX__
+  if (bar (__INT_MAX__ + 1LL) != (-__INT_MAX__ - 1)
+      || bar (2 * (__INT_MAX__ + 1LL)) != (-__INT_MAX__ - 1)
+      || bar (-__LONG_LONG_MAX__ - 1) != (-__INT_MAX__ - 1)
+      || bar ((__INT_MAX__ + 1LL) / 2) != 0)
+    __builtin_abort ();
+#endif
+  return 0;
+}