Transforming `(a * b@[0,1]) != 0` into `((cast)b) & a != 0`
will produce better code as a lot of the time b is defined
by a comparison.
Also since canonicalize `a & -zero_one` into `a * zero_one` we
start to lose information when doing comparisons against 0.
In the case of PR 110992, we lose that `a != 0` on the branch
and then don't do a jump threading like we should.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
PR tree-optimization/110992
gcc/ChangeLog:
* match.pd (`a * zero_one !=/== CST`): New pattern.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/vrp116.c: Update test to avoid the
extra comparison.
* gcc.c-torture/execute/pr110992-1.c: New test.
* gcc.dg/tree-ssa/pr110992-1.c: New test.
* gcc.dg/tree-ssa/pr110992-2.c: New test.
---
gcc/match.pd | 15 +++++++
.../gcc.c-torture/execute/pr110992-1.c | 43 +++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr110992-1.c | 21 +++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr110992-2.c | 17 ++++++++
gcc/testsuite/gcc.dg/tree-ssa/vrp116.c | 2 +-
5 files changed, 97 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr110992-1.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110992-1.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110992-2.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 39c9c81966a..97405e6a5c3 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2197,6 +2197,21 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(if (INTEGRAL_TYPE_P (type))
(bit_and @0 @1)))
+/* (a * b@[0,1]) == CST
+ ->
+ CST == 0 ? (a == CST | b == 0) : (a == CST & b != 0)
+ (a * b@[0,1]) != CST
+ ->
+ CST != 0 ? (a != CST | b == 0) : (a != CST & b != 0) */
+(for cmp (ne eq)
+ (simplify
+ (cmp (mult:cs @0 zero_one_valued_p@1) INTEGER_CST@2)
+ (if ((cmp == EQ_EXPR) ^ (wi::to_wide (@2) != 0))
+ (bit_ior
+ (cmp @0 @2)
+ (convert (bit_xor @1 { build_one_cst (TREE_TYPE (@1)); })))
+ (bit_and (cmp @0 @2) (convert @1)))))
+
(for cmp (tcc_comparison)
icmp (inverted_tcc_comparison)
/* Fold (((a < b) & c) | ((a >= b) & d)) into (a < b ? c : d) & 1. */
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr110992-1.c
b/gcc/testsuite/gcc.c-torture/execute/pr110992-1.c
new file mode 100644
index 00000000000..edb7eb75ef2
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr110992-1.c
@@ -0,0 +1,43 @@
+#define CST 5
+#define OP !=
+#define op_eq ==
+#define op_ne !=
+
+#define function(vol,op, cst) \
+__attribute__((noipa)) \
+_Bool func_##op##_##cst##_##vol(vol int a, vol _Bool b) \
+{ \
+ vol int d = (a * b); \
+ return d op_##op cst; \
+}
+
+#define funcdefs(op,cst) \
+function(,op,cst) \
+function(volatile,op,cst)
+
+#define funcs(f) \
+f(eq,0) \
+f(eq,1) \
+f(eq,5) \
+f(ne,0) \
+f(ne,1) \
+f(ne,5)
+
+funcs(funcdefs)
+
+#define test(op,cst) \
+do { \
+ if(func_##op##_##cst##_(a,b) != func_##op##_##cst##_volatile(a,b))\
+ __builtin_abort(); \
+} while(0);
+
+int main(void)
+{
+ for(int a = -10; a <= 10; a++)
+ {
+ _Bool b = 0;
+ funcs(test)
+ b = 1;
+ funcs(test)
+ }
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110992-1.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr110992-1.c
new file mode 100644
index 00000000000..825fd63f84c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110992-1.c
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fdump-tree-optimized" } */
+static unsigned b;
+static short c = 4;
+void foo(void);
+static short(a)(short d, short g) { return d * g; }
+void e();
+static char f() {
+ b = 0;
+ return 0;
+}
+int main() {
+ int h = b;
+ if ((short)(a(c && e, 65535) & h)) {
+ foo();
+ h || f();
+ }
+}
+
+/* There should be no calls to foo left. */
+/* { dg-final { scan-tree-dump-not " foo " "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110992-2.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr110992-2.c
new file mode 100644
index 00000000000..6082949a218
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110992-2.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fdump-tree-optimized" } */
+static unsigned b;
+static short c = 4;
+void foo(void);
+int main() {
+ int h = b;
+ int d = c != 0;
+ if (h*d) {
+ foo();
+ if (!h) b = 20;
+ }
+}
+
+
+/* There should be no calls to foo left. */
+/* { dg-final { scan-tree-dump-not " foo " "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp116.c
b/gcc/testsuite/gcc.dg/tree-ssa/vrp116.c
index 9e68a774aee..16b31e320a0 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/vrp116.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp116.c
@@ -6,7 +6,7 @@ f (int m1, int m2, int c)
{
int d = m1 > m2;
int e = d * c;
- return e ? m1 : m2;
+ return e;
}
/* { dg-final { scan-tree-dump-times "\\? c_\[0-9\]\\(D\\) : 0" 1 "optimized"
} } */
--
2.31.1
