| Message ID | 20201105161852.551111-1-aldyh@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Drop overflow from constants while building ranges in ranger. | expand |
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); +}
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