From: Jakub Jelinek <jakub@redhat.com>
Date: Wed, 12 Sep 2018 09:18:55 +0000 (+0200)
Subject: re PR middle-end/87248 (Bad code for masked operations involving signed ints)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9095b53a8c4a5663b89db946462ff534fe0836e7;p=gcc.git

re PR middle-end/87248 (Bad code for masked operations involving signed ints)

	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: r264230
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index de60879ea6c..c08654dfe2b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+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.
+
 2018-09-12  Tom de Vries  <tdevries@suse.de>
 
 	* common.opt (gdescribe-dies): Add option.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index bdd24c5969b..3bcf272bd63 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -11607,10 +11607,16 @@ 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 a429bc3d8b9..c32dc771486 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-09-12  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/87248
+	* c-c++-common/torture/pr87248.c: New test.
+
 2018-09-11  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/87172
diff --git a/gcc/testsuite/c-c++-common/torture/pr87248.c b/gcc/testsuite/c-c++-common/torture/pr87248.c
new file mode 100644
index 00000000000..6f89bc9a31c
--- /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;
+}