When I moved two_value to match.pd, I removed the check for the {0,+-1}
as I had placed it after the {0,+-1} case for cond in match.pd.
In the case of {0,+-1} and non boolean, before we would optmize those
case to just `(convert)a` but after we would get `(convert)(a != 0)`
which was not handled anyways to just `(convert)a`.
So this adds a pattern to match `(convert)(zeroone != 0)` and simplify
to `(convert)zeroone`.
In the bug report, we do finally optimize `(convert)(zeroone != 0)` to
`zeroone` in VRP2 but that in itself is too late and we miss other
optimizations that would have happened.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
gcc/ChangeLog:
PR tree-optimization/110539
* match.pd ((convert)(zeroone !=/== 0)): Match
and simplify to ((convert)zeroone)){,^1}.
gcc/testsuite/ChangeLog:
PR tree-optimization/110539
* gcc.dg/tree-ssa/pr110539-1.c: New test.
* gcc.dg/tree-ssa/pr110539-2.c: New test.
* gcc.dg/tree-ssa/pr110539-3.c: New test.
---
gcc/match.pd | 15 +++++
gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c | 12 ++++
gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c | 12 ++++
gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c | 70 ++++++++++++++++++++++
4 files changed, 109 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
diff --git a/gcc/match.pd b/gcc/match.pd
index c709153217a..87767a7778b 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2060,6 +2060,21 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(vec_cond:s (icmp@1 @4 @5) @3 integer_zerop))
(vec_cond @0 @2 @3)))
+#if GIMPLE
+/* This cannot be done on generic as fold has the
+ exact opposite transformation:
+ `Fold ~X & 1 as (X & 1) == 0.`
+ `Fold (X ^ 1) & 1 as (X & 1) == 0.` */
+/* (convert)(zeroone != 0) into (convert)zeroone */
+/* (convert)(zeroone == 0) into (convert)(zeroone^1) */
+(for neeq (ne eq)
+ (simplify
+ (convert (neeq zero_one_valued_p@0 integer_zerop))
+ (if (neeq == NE_EXPR)
+ (convert @0)
+ (convert (bit_xor @0 { build_one_cst (TREE_TYPE (@0)); } )))))
+#endif
+
/* Transform X & -Y into X * Y when Y is { 0 or 1 }. */
(simplify
(bit_and:c (convert? (negate zero_one_valued_p@0)) @1)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
new file mode 100644
index 00000000000..6ba864cdd13
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized" } */
+int f(int a)
+{
+ int b = a & 1;
+ int c = b != 0;
+ return c == b;
+}
+
+/* This should be optimized to just return 1; */
+/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
+/* { dg-final { scan-tree-dump "return 1;" "optimized"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
new file mode 100644
index 00000000000..17874d349ef
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized" } */
+int f(int a)
+{
+ int b = a & 1;
+ int c = b == 0;
+ return c == b;
+}
+
+/* This should be optimized to just return 0; */
+/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
+/* { dg-final { scan-tree-dump "return 0;" "optimized"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
new file mode 100644
index 00000000000..c8ef6f56dcd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
@@ -0,0 +1,70 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+void foo(void);
+static int a, c = 1;
+static short b;
+static int *d = &c, *e = &a;
+static int **f = &d;
+void __assert_fail() __attribute__((__noreturn__));
+static void g(short h) {
+ if (*d)
+ ;
+ else {
+ if (e) __assert_fail();
+ if (a) {
+ __builtin_unreachable();
+ } else
+ __assert_fail();
+ }
+ if ((((0, 0) || h) == h) + b) *f = 0;
+}
+int main() {
+ int i = 0 != 10 & a;
+ g(i);
+ *e = 9;
+ e = 0;
+ if (d == 0)
+ ;
+ else
+ foo();
+ ;
+}
+/* The call to foo should be optimized away. */
+/* The missed optimization at -O2 here was:
+ int b = a & 1;
+ int c = b != 0;
+ int d = c == b;
+ not being optimized to 1 early enough, it is done in vrp2 but
+ that is too late.
+ In phiopt2 we got:
+ _17 = i_7 != 0;
+ _12 = (int) _17;
+ if (i_7 == _12)
+ goto <bb 9>; [50.00%]
+ else
+ goto <bb 10>; [50.00%]
+
+ <bb 9> [local count: 268435456]:
+ d = 0B;
+
+ <bb 10> [local count: 536870913]:
+ e.1_3 = e;
+ *e.1_3 = 9;
+ e = 0B;
+ d.2_4 = d;
+ if (d.2_4 == 0B)
+
+ The first if is not optimized before, until vrp2 which is
+ too late as there are no passes which will then find the
+ load of d in `d.2_4 = d;` was `0B` after vrp2.
+
+ Now we optimize dom2 because phiopt2 we just get:
+ _12 = i_7;
+ if (i_7 == _12)
+ goto <bb 9>; [50.00%]
+ else
+ goto <bb 10>; [50.00%]
+ */
+
+/* { dg-final { scan-tree-dump-not "foo \\(\\)" "optimized"} } */
--
2.31.1
