re PR tree-optimization/67953 (match.pd: X - (X / Y) * Y wrong on change of sign)

	PR tree-optimization/67953
	* match.pd (X - (X / Y) * Y): Don't change signedness of @0.

	* gcc.dg/fold-minus-6.c (fn4): Change the type of A to
	unsigned.
	* gcc.dg/torture/pr67953.c: New test.

From-SVN: r228839

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5a0fde8..6dec962 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2015-10-15  Marek Polacek  <polacek@redhat.com>
+
+       PR tree-optimization/67953
+       * match.pd (X - (X / Y) * Y): Don't change signedness of @0.
+
 2015-10-15  Jiong Wang  <jiong.wang@arm.com>
 
        * config.gcc: Recognize "." in architecture base name for AArch64.

diff --git a/gcc/match.pd b/gcc/match.pd
index 655c9ff..24e19a9 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -267,7 +267,8 @@ along with GCC; see the file COPYING3.  If not see
 /* X - (X / Y) * Y is the same as X % Y.  */
 (simplify
  (minus (convert1? @0) (convert2? (mult (trunc_div @0 @1) @1)))
- (if (INTEGRAL_TYPE_P (type) || VECTOR_INTEGER_TYPE_P (type))
+ (if ((INTEGRAL_TYPE_P (type) || VECTOR_INTEGER_TYPE_P (type))
+      && TYPE_UNSIGNED (TREE_TYPE (@0)) == TYPE_UNSIGNED (type))
   (trunc_mod (convert @0) (convert @1))))
 
 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f45ab81..631d8a7 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2015-10-15  Marek Polacek  <polacek@redhat.com>
+
+       PR tree-optimization/67953
+       * gcc.dg/fold-minus-6.c (fn4): Change the type of A to
+       unsigned.
+       * gcc.dg/torture/pr67953.c: New test.
+
 2015-10-14  Jeff Law  <law@redhat.com>
 
        * gcc.dg/tree-ssa/ssa-dom-thread-2.c: Deleted.  The six functions

diff --git a/gcc/testsuite/gcc.dg/fold-minus-6.c b/gcc/testsuite/gcc.dg/fold-minus-6.c
index 1c22c25..1535452 100644 (file)
--- a/gcc/testsuite/gcc.dg/fold-minus-6.c
+++ b/gcc/testsuite/gcc.dg/fold-minus-6.c
@@ -20,7 +20,7 @@ fn3 (long int x)
 }
 
 int
-fn4 (int a, int b)
+fn4 (unsigned int a, int b)
 {
   return a - (unsigned) ((a / b) * b);
 }

diff --git a/gcc/testsuite/gcc.dg/torture/pr67953.c b/gcc/testsuite/gcc.dg/torture/pr67953.c
new file mode 100644 (file)
index 0000000..68ff013
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr67953.c
@@ -0,0 +1,36 @@
+/* PR tree-optimization/67953 */
+/* { dg-do run } */
+
+unsigned int
+fn1 (signed int a)
+{
+  return (unsigned int) a - ((a / 3) * 3);
+}
+
+unsigned int
+fn2 (signed int a)
+{
+  return a - ((a / 3) * 3);
+}
+
+unsigned int
+fn3 (int a)
+{
+  return a - (unsigned) ((a / 3) * 3);
+}
+
+signed int
+fn4 (int a)
+{
+  return (unsigned) a - (unsigned) ((a / 3) * 3);
+}
+
+int
+main ()
+{
+  if (fn1 (-5) != -2
+      || fn2 (-5) != -2
+      || fn3 (-5) != -2
+      || fn4 (-5) != -2)
+    __builtin_abort ();
+}