Hi Richard,
The attached patch tries to fix PR35691, by adding the following two
transforms to match.pd:
(x == 0 && y == 0) -> (x | typeof(x)(y)) == 0.
(x != 0 || y != 0) -> (x | typeof(x)(y)) != 0.
For GENERIC, the "and" operator is truth_andif_expr, and it seems for GIMPLE,
it gets transformed to bit_and_expr
so to match for both GENERIC and GIMPLE, I had to guard the for-stmt:
#if GENERIC
(for op (truth_andif truth_orif)
#elif GIMPLE
(for op (bit_and bit_ior)
#endif
Is that OK ?
Bootstrap+test running on x86_64-unknown-linux-gnu.
Thanks,
Prathamesh
2016-11-03 Prathamesh Kulkarni <prathamesh.kulka...@linaro.org>
PR middle-end/35691
* match.pd: Add following two patterns:
(x == 0 & y == 0) -> (x | typeof(x)(y)) == 0.
(x != 0 | y != 0) -> (x | typeof(x)(y)) != 0.
testsuite/
* gcc.dg/pr35691-1.c: New test-case.
* gcc.dg/pr35691-2.c: Likewise.
* gcc.dg/pr35691-3.c: Likewise.
* gcc.dg/pr35691-4.c: Likewise.
diff --git a/gcc/match.pd b/gcc/match.pd
index 48f7351..65930bb 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -519,6 +519,23 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(if (TYPE_UNSIGNED (type))
(bit_and @0 (bit_not (lshift { build_all_ones_cst (type); } @1)))))
+/* PR35691: Transform
+ (x == 0 & y == 0) -> (x | typeof(x)(y)) == 0.
+ (x != 0 | y != 0) -> (x | typeof(x)(y)) != 0. */
+
+#if GENERIC
+(for op (truth_andif truth_orif)
+#elif GIMPLE
+(for op (bit_and bit_ior)
+#endif
+ cmp (eq ne)
+ (simplify
+ (op (cmp @0 integer_zerop) (cmp @1 integer_zerop))
+ (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
+ && INTEGRAL_TYPE_P (TREE_TYPE (@1))
+ && TYPE_PRECISION (TREE_TYPE (@0)) == TYPE_PRECISION (TREE_TYPE (@1)))
+ (cmp (bit_ior @0 (convert @1)) { build_zero_cst (TREE_TYPE (@0)); }))))
+
/* Fold (A & ~B) - (A & B) into (A ^ B) - B. */
(simplify
(minus (bit_and:cs @0 (bit_not @1)) (bit_and:cs @0 @1))
diff --git a/gcc/testsuite/gcc.dg/pr35691-1.c b/gcc/testsuite/gcc.dg/pr35691-1.c
new file mode 100644
index 0000000..25a7ace
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr35691-1.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-gimple" } */
+
+int foo1(int z0, unsigned z1)
+{
+ return (z0 == 0) && (z1 == 0);
+}
+
+/* { dg-final { scan-tree-dump-not "z1.\[0-9\]*_\[0-9\]* = (int) z1" "gimple"
} } */
diff --git a/gcc/testsuite/gcc.dg/pr35691-2.c b/gcc/testsuite/gcc.dg/pr35691-2.c
new file mode 100644
index 0000000..5211f815
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr35691-2.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-forwprop-details" } */
+
+int foo(int z0, unsigned z1)
+{
+ int t0 = (z0 == 0);
+ int t1 = (z1 == 0);
+ int t2 = (t0 && t1);
+ return t2;
+}
+
+/* { dg-final { scan-tree-dump "gimple_simplified to _\[0-9\]* = \\(int\\)
z1_\[0-9\]*\\(D\\);" "forwprop1" } } */
diff --git a/gcc/testsuite/gcc.dg/pr35691-3.c b/gcc/testsuite/gcc.dg/pr35691-3.c
new file mode 100644
index 0000000..134bbdf
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr35691-3.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-gimple" } */
+
+int foo1(int z0, unsigned z1)
+{
+ return (z0 != 0) || (z1 != 0);
+}
+
+/* { dg-final { scan-tree-dump-not "z1.\[0-9\]*_\[0-9\]* = (int) z1" "gimple"
} } */
diff --git a/gcc/testsuite/gcc.dg/pr35691-4.c b/gcc/testsuite/gcc.dg/pr35691-4.c
new file mode 100644
index 0000000..90cbf6d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr35691-4.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-forwprop-details" } */
+
+int foo(int z0, unsigned z1)
+{
+ int t0 = (z0 != 0);
+ int t1 = (z1 != 0);
+ int t2 = (t0 || t1);
+ return t2;
+}
+
+/* { dg-final { scan-tree-dump "gimple_simplified to _\[0-9\]* = \\(int\\)
z1_\[0-9\]*\\(D\\);" "forwprop1" } } */
