Sometimes the overflow flag will leak into the IL. Drop it while
creating ranges.
There are various places we could plug this. This patch just plugs things
at get_tree_range which is the entry point for ranges from tree expressions.
It fixes the PR, and probably fixes the ranger entirely, but we may need
to revisit this.
For example, I looked to see if there were other places that created
ranges with TREE_OVERFLOW set, and there are various. For example,
the following code pattern appears multiple times in vr-values.c:
else if (is_gimple_min_invariant (op0))
vr0.set (op0);
This can pick up TREE_OVERFLOW from the IL if present. However, the
ranger won't see them so we're good.
At some point we should audit all this. Or perhaps just nuke all
TREE_OVERFLOW's at irange::set.
For now, this will do.
Pushed.
gcc/ChangeLog:
PR tree-optimization/97721
* gimple-range.cc (get_tree_range): Drop overflow from constants.
gcc/testsuite/ChangeLog:
* gcc.dg/pr97721.c: New test.
---
gcc/gimple-range.cc | 2 ++
gcc/testsuite/gcc.dg/pr97721.c | 13 +++++++++++++
2 files changed, 15 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/pr97721.c
diff --git a/gcc/gimple-range.cc b/gcc/gimple-range.cc
index ef65e00cc1d..0c8ec40448f 100644
--- a/gcc/gimple-range.cc
+++ b/gcc/gimple-range.cc
@@ -165,6 +165,8 @@ get_tree_range (irange &r, tree expr)
switch (TREE_CODE (expr))
{
case INTEGER_CST:
+ if (TREE_OVERFLOW_P (expr))
+ expr = drop_tree_overflow (expr);
r.set (expr, expr);
return true;
diff --git a/gcc/testsuite/gcc.dg/pr97721.c b/gcc/testsuite/gcc.dg/pr97721.c
new file mode 100644
index 00000000000..c2a2848ba13
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr97721.c
@@ -0,0 +1,13 @@
+// { dg-do compile }
+// { dg-options "-O -fno-tree-dominator-opts" }
+
+int ot;
+
+void
+z6 (char *tw)
+{
+ while (ot >= 0)
+ --ot;
+
+ __builtin_strcpy (&tw[ot], tw);
+}
--
2.26.2
