Hi!
While fixing libgcc2.c (__mulvDI3), I've noticed that while we
optimize x == 0 && y == 0 into (x | y) == 0, we don't optimize
analogical x == -1 && y == -1 into (x & y) == -1.
The following patch does that, bootstrapped/regtested on x86_64-linux and
i686-linux, ok for trunk?
2017-09-22 Jakub Jelinek <ja...@redhat.com>
PR middle-end/35691
* match.pd: Simplify x == -1 & y == -1 into (x & y) == -1
and x != -1 | y != -1 into (x & y) != -1.
* gcc.dg/pr35691-1.c: Use -fdump-tree-forwprop1-details
instead of -fdump-tree-forwprop-details in dg-options.
* gcc.dg/pr35691-2.c: Likewise.
* gcc.dg/pr35691-3.c: New test.
* gcc.dg/pr35691-4.c: New test.
--- gcc/match.pd.jj 2017-09-15 20:42:29.000000000 +0200
+++ gcc/match.pd 2017-09-22 13:34:29.413534762 +0200
@@ -630,17 +630,26 @@ 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. */
(for bitop (bit_and bit_ior)
cmp (eq ne)
+ /* PR35691: Transform
+ (x == 0 & y == 0) -> (x | typeof(x)(y)) == 0.
+ (x != 0 | y != 0) -> (x | typeof(x)(y)) != 0. */
(simplify
(bitop (cmp @0 integer_zerop@2) (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)) @2))))
+ && INTEGRAL_TYPE_P (TREE_TYPE (@1))
+ && TYPE_PRECISION (TREE_TYPE (@0)) == TYPE_PRECISION (TREE_TYPE (@1)))
+ (cmp (bit_ior @0 (convert @1)) @2)))
+ /* Transform:
+ (x == -1 & y == -1) -> (x & typeof(x)(y)) == -1.
+ (x != -1 | y != -1) -> (x & typeof(x)(y)) != -1. */
+ (simplify
+ (bitop (cmp @0 integer_all_onesp@2) (cmp @1 integer_all_onesp))
+ (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_and @0 (convert @1)) @2))))
/* Fold (A & ~B) - (A & B) into (A ^ B) - B. */
(simplify
--- gcc/testsuite/gcc.dg/pr35691-1.c.jj 2016-11-09 15:22:31.000000000 +0100
+++ gcc/testsuite/gcc.dg/pr35691-1.c 2017-09-22 13:58:32.665455251 +0200
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-forwprop-details" } */
+/* { dg-options "-O2 -fdump-tree-forwprop1-details" } */
int foo(int z0, unsigned z1)
{
--- gcc/testsuite/gcc.dg/pr35691-2.c.jj 2016-11-09 15:22:32.000000000 +0100
+++ gcc/testsuite/gcc.dg/pr35691-2.c 2017-09-22 13:58:38.174386317 +0200
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-forwprop-details" } */
+/* { dg-options "-O2 -fdump-tree-forwprop1-details" } */
int foo(int z0, unsigned z1)
{
--- gcc/testsuite/gcc.dg/pr35691-3.c.jj 2017-09-22 13:55:36.186663576 +0200
+++ gcc/testsuite/gcc.dg/pr35691-3.c 2017-09-22 13:58:44.070312539 +0200
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-forwprop1-details" } */
+
+int foo(int z0, unsigned z1)
+{
+ int t0 = (z0 == -1);
+ int t1 = (z1 == -1U);
+ int t2 = (t0 & t1);
+ return t2;
+}
+
+/* { dg-final { scan-tree-dump "gimple_simplified to _\[0-9\]* = \\(int\\)
z1_\[0-9\]*\\(D\\);" "forwprop1" } } */
--- gcc/testsuite/gcc.dg/pr35691-4.c.jj 2017-09-22 13:55:39.855617665 +0200
+++ gcc/testsuite/gcc.dg/pr35691-4.c 2017-09-22 13:58:50.132236685 +0200
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-forwprop1-details" } */
+
+int foo(int z0, unsigned z1)
+{
+ int t0 = (z0 != -1);
+ int t1 = (z1 != -1U);
+ int t2 = (t0 | t1);
+ return t2;
+}
+
+/* { dg-final { scan-tree-dump "gimple_simplified to _\[0-9\]* = \\(int\\)
z1_\[0-9\]*\\(D\\);" "forwprop1" } } */
Jakub
