match.pd: Disallow side-effects in GENERIC for non-COND_EXPR to COND_EXPR simplificat...

As the following testcases show (the first one reported, last two
found by code inspection), we need to disallow side-effects
in simplifications that turn some unconditional expression into conditional
one.  From my little understanding of genmatch.c, it is able to
automatically disallow side effects if the same operand is used multiple
times in the match pattern, maybe if it is used multiple times in the
replacement pattern, and if it is used in conditional contexts in the match
pattern, could it be taught to handle this case too?  If yes, perhaps
just the first hunk could be usable for 8/9 backports (+ the testcases).

2020-02-15  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/93744
	* match.pd (((m1 >/</>=/<= m2) * d -> (m1 >/</>=/<= m2) ? d : 0,
	A - ((A - B) & -(C cmp D)) -> (C cmp D) ? B : A,
	A + ((B - A) & -(C cmp D)) -> (C cmp D) ? B : A): For GENERIC, make
	sure @2 in the first and @1 in the other patterns has no side-effects.

	* gcc.c-torture/execute/pr93744-1.c: New test.
	* gcc.c-torture/execute/pr93744-2.c: New test.
	* gcc.c-torture/execute/pr93744-3.c: New test.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 22f990a3088cf1d4ef2a4c1c4cf8689a79ba58b5..3ef5b4d68f74bd077d3cf3efe500b98ee02954fc 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2020-02-15  Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/93744
+       * match.pd (((m1 >/</>=/<= m2) * d -> (m1 >/</>=/<= m2) ? d : 0,
+       A - ((A - B) & -(C cmp D)) -> (C cmp D) ? B : A,
+       A + ((B - A) & -(C cmp D)) -> (C cmp D) ? B : A): For GENERIC, make
+       sure @2 in the first and @1 in the other patterns has no side-effects.
+
 2020-02-15  David Malcolm  <dmalcolm@redhat.com>
            Bernd Edlinger  <bernd.edlinger@hotmail.de>
 

diff --git a/gcc/match.pd b/gcc/match.pd
index 73834c255935930e2c93d7ba21a126f17d222882..19df0c404a47242b6b5af332fc4d6528722f0fe8 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1472,7 +1472,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 (for cmp (gt lt ge le)
 (simplify
  (mult (convert (cmp @0 @1)) @2)
-  (cond (cmp @0 @1) @2 { build_zero_cst (type); })))
+  (if (GIMPLE || !TREE_SIDE_EFFECTS (@2))
+   (cond (cmp @0 @1) @2 { build_zero_cst (type); }))))
 
 /* For integral types with undefined overflow and C != 0 fold
    x * C EQ/NE y * C into x EQ/NE y.  */
@@ -2709,7 +2710,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
        && TREE_CODE (TREE_TYPE (@4)) != BOOLEAN_TYPE
        && INTEGRAL_TYPE_P (TREE_TYPE (@5))
        && (TYPE_PRECISION (TREE_TYPE (@4)) >= TYPE_PRECISION (type)
-          || !TYPE_UNSIGNED (TREE_TYPE (@4))))
+          || !TYPE_UNSIGNED (TREE_TYPE (@4)))
+       && (GIMPLE || !TREE_SIDE_EFFECTS (@1)))
    (cond (cmp @2 @3) @1 @0)))
  (simplify
   (plus:c @0 (bit_and:c (minus @1 @0)
@@ -2719,7 +2721,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
        && TREE_CODE (TREE_TYPE (@4)) != BOOLEAN_TYPE
        && INTEGRAL_TYPE_P (TREE_TYPE (@5))
        && (TYPE_PRECISION (TREE_TYPE (@4)) >= TYPE_PRECISION (type)
-          || !TYPE_UNSIGNED (TREE_TYPE (@4))))
+          || !TYPE_UNSIGNED (TREE_TYPE (@4)))
+       && (GIMPLE || !TREE_SIDE_EFFECTS (@1)))
    (cond (cmp @2 @3) @1 @0))))
 
 /* Simplifications of shift and rotates.  */

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3059e238ff31c8c4275e4e67b5909618f79cb0d8..77c781a40e8b609de10e988da99c4db7ae987954 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2020-02-15  Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/93744
+       * gcc.c-torture/execute/pr93744-1.c: New test.
+       * gcc.c-torture/execute/pr93744-2.c: New test.
+       * gcc.c-torture/execute/pr93744-3.c: New test.
+
 2020-02-14  Jakub Jelinek  <jakub@redhat.com>
 
        PR c++/61414

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr93744-1.c b/gcc/testsuite/gcc.c-torture/execute/pr93744-1.c
new file mode 100644 (file)
index 0000000..3229c9b
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr93744-1.c
@@ -0,0 +1,14 @@
+/* PR tree-optimization/93744 */
+
+typedef int I;
+
+int
+main ()
+{
+  int a = 0;
+  I b = 0;
+  (a > 0) * (b |= 2);
+  if (b != 2)
+    __builtin_abort ();
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr93744-2.c b/gcc/testsuite/gcc.c-torture/execute/pr93744-2.c
new file mode 100644 (file)
index 0000000..0c1baaa
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr93744-2.c
@@ -0,0 +1,21 @@
+/* PR tree-optimization/93744 */
+
+int w;
+
+int
+foo (int x, int y, int z)
+{
+  int r = z - ((z - w++) & -(x < y));
+  return r;
+}
+
+int
+main ()
+{
+  w = 4;
+  if (foo (5, 7, 12) != 4 || w != 5)
+    __builtin_abort ();
+  if (foo (7, 5, 12) != 12 || w != 6)
+    __builtin_abort ();
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr93744-3.c b/gcc/testsuite/gcc.c-torture/execute/pr93744-3.c
new file mode 100644 (file)
index 0000000..8542c7c
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr93744-3.c
@@ -0,0 +1,21 @@
+/* PR tree-optimization/93744 */
+
+int w;
+
+int
+foo (int x, int y, int z)
+{
+  int r = z + ((w++ - z) & -(x < y));
+  return r;
+}
+
+int
+main ()
+{
+  w = 4;
+  if (foo (5, 7, 12) != 4 || w != 5)
+    __builtin_abort ();
+  if (foo (7, 5, 12) != 12 || w != 6)
+    __builtin_abort ();
+  return 0;
+}