On Wed, Mar 06, 2024 at 11:45:42AM +0100, Richard Biener wrote:
> OK, though feel free to add ARG_UNUSED to 'captures' as well.
Ok, done below.
> I think the INTEGRAL_TYPE_P should be redundant - the pattern
> should work for vectors and complex as well (with integer components
> which integer_zerop constrains).
Guess you're right. I think it is correct as is for both complex and
int vector, while float etc. shouldn't appear there because of the
integer_zerop and pointer because we don't do multiplication on pointer
types.
That said, it won't really actually match the vector int case actually
emitted, where we have a VEC_COND_EXPR, added those as new patterns.
And it doesn't match what is emitted for _Complex, though I think it
isn't that important to simplify that.
_Complex int
freddy (_Complex int x)
{
return x * !x;
}
_Complex int
garply (_Complex int x)
{
return x * (x == 0);
}
results in original in:
return COMPLEX_EXPR <REALPART_EXPR <SAVE_EXPR <x>> == 0 && IMAGPART_EXPR
<SAVE_EXPR <x>> == 0, 0> * x;
and
return (x == __complex__ (0, 0) ? __complex__ (1, 0) : __complex__ (0, 0)) *
x;
but after gimplification it is already something that is really
too hard to optimize.
So, is the following still ok if it passes bootstrap/regtest?
2024-03-06 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/114009
* genmatch.cc (decision_tree::gen): Emit ARG_UNUSED for captures
argument even for GENERIC, not just for GIMPLE.
* match.pd (a * !a -> 0): New simplifications.
* gcc.dg/tree-ssa/pr114009.c: New test.
--- gcc/genmatch.cc.jj 2024-02-26 10:09:16.594613314 +0100
+++ gcc/genmatch.cc 2024-03-06 13:47:35.001458638 +0100
@@ -4071,7 +4071,7 @@ decision_tree::gen (vec <FILE *> &files,
for (unsigned i = 0;
i < as_a <expr *>(s->s->s->match)->ops.length (); ++i)
fp_decl (f, " tree ARG_UNUSED (_p%d),", i);
- fp_decl (f, " tree *captures");
+ fp_decl (f, " tree *ARG_UNUSED (captures)");
}
for (unsigned i = 0; i < s->s->s->for_subst_vec.length (); ++i)
{
--- gcc/match.pd.jj 2024-03-06 09:34:36.608271525 +0100
+++ gcc/match.pd 2024-03-06 13:58:27.400588289 +0100
@@ -1219,6 +1219,17 @@ (define_operator_list SYNC_FETCH_AND_AND
&& tree_nop_conversion_p (type, TREE_TYPE (@1)))
(lshift @0 @2)))
+/* Fold a * !a into 0. */
+(simplify
+ (mult:c @0 (convert? (eq @0 integer_zerop)))
+ { build_zero_cst (type); })
+(simplify
+ (mult:c @0 (vec_cond (eq @0 integer_zerop) @1 integer_zerop))
+ { build_zero_cst (type); })
+(simplify
+ (mult:c @0 (vec_cond (ne @0 integer_zerop) integer_zerop @1))
+ { build_zero_cst (type); })
+
/* Shifts by precision or greater result in zero. */
(for shift (lshift rshift)
(simplify
--- gcc/testsuite/gcc.dg/tree-ssa/pr114009.c.jj 2024-03-06 13:44:33.481924326
+0100
+++ gcc/testsuite/gcc.dg/tree-ssa/pr114009.c 2024-03-06 14:04:09.724918390
+0100
@@ -0,0 +1,33 @@
+/* PR tree-optimization/114009 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wno-psabi -fdump-tree-forwprop1" } */
+/* { dg-final { scan-tree-dump-times " return 0;" 3 "forwprop1" } } */
+/* { dg-final { scan-tree-dump-times " (?:return|<retval> =) { 0, 0, 0, 0 };"
1 "forwprop1" } } */
+
+int
+foo (int x)
+{
+ x = (x / 2) * 2;
+ return (!x) * x;
+}
+
+int
+bar (int x, int y)
+{
+ (void) x;
+ return y * !y;
+}
+
+unsigned long long
+baz (unsigned long long x)
+{
+ return (!x) * x;
+}
+
+typedef int V __attribute__((vector_size (4 * sizeof (int))));
+
+V
+qux (V x)
+{
+ return x * (x == 0);
+}
Jakub
