re PR middle-end/71762 (~X & Y to X < Y doesn't work for uninitialized values)

2016-11-23  Richard Biener  <rguenther@suse.de>

	PR middle-end/71762
	* match.pd ((~X & Y) -> X < Y, (X & ~Y) -> Y < X,
	(~X | Y) -> X <= Y, (X | ~Y) -> Y <= X): Remove.

	* gcc.dg/torture/pr71762-1.c: New testcase.
	* gcc.dg/torture/pr71762-2.c: Likewise.
	* gcc.dg/torture/pr71762-3.c: Likewise.
	* gcc.dg/tree-ssa/forwprop-28.c: XFAIL.

From-SVN: r242747

6 files changed, 71 insertions, 27 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c0c529f..192d6e4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2016-11-23  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/71762
+	* match.pd ((~X & Y) -> X < Y, (X & ~Y) -> Y < X,
+	(~X | Y) -> X <= Y, (X | ~Y) -> Y <= X): Remove.
+
+2016-11-23  Richard Biener  <rguenther@suse.de>
+
 	PR lto/78472
 	* tree.c (gimple_canonical_types_compatible_p): Ignore zero-sized
 	fields.
diff --git a/gcc/match.pd b/gcc/match.pd
index 3fece35..6665412 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -963,33 +963,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (op:c truth_valued_p@0 (logical_inverted_value @0))
   { constant_boolean_node (op == NE_EXPR ? true : false, type); }))
 
-/* If arg1 and arg2 are booleans (or any single bit type)
-   then try to simplify:
-
-   (~X & Y) -> X < Y
-   (X & ~Y) -> Y < X
-   (~X | Y) -> X <= Y
-   (X | ~Y) -> Y <= X
-
-   But only do this if our result feeds into a comparison as
-   this transformation is not always a win, particularly on
-   targets with and-not instructions.
-   -> simplify_bitwise_binary_boolean */
-(simplify
-  (ne (bit_and:c (bit_not @0) @1) integer_zerop)
-  (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
-       && TYPE_PRECISION (TREE_TYPE (@1)) == 1)
-   (if (TYPE_UNSIGNED (TREE_TYPE (@1)))
-    (lt @0 @1)
-    (gt @0 @1))))
-(simplify
-  (ne (bit_ior:c (bit_not @0) @1) integer_zerop)
-  (if (INTEGRAL_TYPE_P (TREE_TYPE (@1))
-       && TYPE_PRECISION (TREE_TYPE (@1)) == 1)
-   (if (TYPE_UNSIGNED (TREE_TYPE (@1)))
-    (le @0 @1)
-    (ge @0 @1))))
-
 /* ~~x -> x */
 (simplify
   (bit_not (bit_not @0))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f4306f0..64fbed7 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,13 @@
 2016-11-23  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/71762
+	* gcc.dg/torture/pr71762-1.c: New testcase.
+	* gcc.dg/torture/pr71762-2.c: Likewise.
+	* gcc.dg/torture/pr71762-3.c: Likewise.
+	* gcc.dg/tree-ssa/forwprop-28.c: XFAIL.
+
+2016-11-23  Richard Biener  <rguenther@suse.de>
+
 	PR lto/78472
 	* g++.dg/lto/pr78472_0.c: New testcase.
 	* g++.dg/lto/pr78472_1.C: Likewise.
diff --git a/gcc/testsuite/gcc.dg/torture/pr71762-1.c b/gcc/testsuite/gcc.dg/torture/pr71762-1.c
new file mode 100644
index 0000000..d20cbc3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr71762-1.c
@@ -0,0 +1,18 @@
+/* { dg-do run } */
+/* { dg-additional-options "-fdisable-rtl-init-regs" } */
+
+static _Bool
+foo (_Bool a, _Bool b)
+{
+  int x = a && ! b;
+  return x != 0;
+}
+
+int y = 1;
+int main()
+{
+  _Bool x;
+  if (foo (x, y))
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/torture/pr71762-2.c b/gcc/testsuite/gcc.dg/torture/pr71762-2.c
new file mode 100644
index 0000000..65047cb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr71762-2.c
@@ -0,0 +1,17 @@
+/* { dg-do run } */
+
+static _Bool
+foo (_Bool a, _Bool b)
+{
+  int x = a && ! b;
+  return x != 0;
+}
+
+int y = 1;
+int main()
+{
+  _Bool x[32];
+  if (foo (x[1], y))
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/torture/pr71762-3.c b/gcc/testsuite/gcc.dg/torture/pr71762-3.c
new file mode 100644
index 0000000..4fd5f98
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr71762-3.c
@@ -0,0 +1,22 @@
+/* { dg-do run } */
+
+static _Bool
+foo (_Bool a, _Bool b)
+{
+  int x = a && ! b;
+  return x != 0;
+}
+
+int y = 1;
+int main()
+{
+  register _Bool x
+  /* Add register spec for the argv parameter to main.  */
+#if __i386__ || __x86_64__
+      __asm__("%esi")
+#endif
+    ;
+  if (foo (x, y))
+    __builtin_abort ();
+  return 0;
+}