When range_of_stmt invokes prefill_name to evaluate unvisited
dependneciesit should not mark visited names as always_current.
when raner_cache::get_globaL_range() is invoked with the optional
"current_p" flag, it triggers additional functionality. This call is
meant to be from within ranger and it is understood that if the current
value is not current, set_global_range will always be called later with
a value. Thus it sets the always_current flag in the temporal cache to
avoid computation cycles.
the prefill_stmt_dependencies () mechanism within ranger is intended to
emulate the bahaviour od range_of_stmt on an arbitrarily long series of
unresolved dependencies without triggering the overhead of huge call
chains from the range_of_expr/range_on_entry/range_on_exit routines.
Rather, it creates a stack of unvisited names, and invokes range_of_stmt
on them directly in order to get initial cache values for each ssa-name.
The issue in this PR was that routine was incorrectly invoking the
get_global_cache to determine whether there was a global value. If
there was, it would move on to the next dependency without invoking
set_global_range to clear the always_current flag.
What it soudl have been doing was simply checking if there as a global
value, and if there was not, add the name for processingand THEN invoke
get_global_value to do all the special processing.
Bootstraps on x86_64-pc-linux-gnu with no regressions. Pushed.
Andrew
From e9be59f7d2dc6b302cf85ad69b0a77dee89ec809 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacl...@redhat.com>
Date: Thu, 7 Sep 2023 11:15:50 -0400
Subject: [PATCH] Some ssa-names get incorrectly marked as always_current.
When range_of_stmt invokes prefill_name to evaluate unvisited dependencies
it should not mark already visited names as always_current.
PR tree-optimization/110875
gcc/
* gimple-range.cc (gimple_ranger::prefill_name): Only invoke
cache-prefilling routine when the ssa-name has no global value.
gcc/testsuite/
* gcc.dg/pr110875.c: New.
---
gcc/gimple-range.cc | 10 +++++++---
gcc/testsuite/gcc.dg/pr110875.c | 34 +++++++++++++++++++++++++++++++++
2 files changed, 41 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr110875.c
diff --git a/gcc/gimple-range.cc b/gcc/gimple-range.cc
index 01173c58f02..13c3308d537 100644
--- a/gcc/gimple-range.cc
+++ b/gcc/gimple-range.cc
@@ -351,10 +351,14 @@ gimple_ranger::prefill_name (vrange &r, tree name)
if (!gimple_range_op_handler::supported_p (stmt) && !is_a<gphi *> (stmt))
return;
- bool current;
// If this op has not been processed yet, then push it on the stack
- if (!m_cache.get_global_range (r, name, current))
- m_stmt_list.safe_push (name);
+ if (!m_cache.get_global_range (r, name))
+ {
+ bool current;
+ // Set the global cache value and mark as alway_current.
+ m_cache.get_global_range (r, name, current);
+ m_stmt_list.safe_push (name);
+ }
}
// This routine will seed the global cache with most of the dependencies of
diff --git a/gcc/testsuite/gcc.dg/pr110875.c b/gcc/testsuite/gcc.dg/pr110875.c
new file mode 100644
index 00000000000..4d6ecbca0c8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110875.c
@@ -0,0 +1,34 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-vrp2" } */
+
+void foo(void);
+static int a, b;
+static int *c = &a, *d;
+static unsigned e;
+static short f;
+static unsigned g(unsigned char h, char i) { return h + i; }
+int main() {
+ d = &a;
+ int *j = d;
+ e = -27;
+ for (; e > 18; e = g(e, 6)) {
+ a = 0;
+ for (; a != -3; a--) {
+ if (0 != a ^ *j)
+ for (; b; b++) f = -f;
+ else if (*c) {
+ foo();
+ break;
+ }
+ if (!(((e) >= 235) && ((e) <= 4294967269))) {
+ __builtin_unreachable();
+ }
+ b = 0;
+ }
+ }
+}
+
+
+/* { dg-final { scan-tree-dump-not "foo" "vrp2" } } */
+
+
--
2.41.0