From 0ebadbad7c92133c467f7aed6f3c16a9e3b55774 Mon Sep 17 00:00:00 2001 Message-ID: <0ebadbad7c92133c467f7aed6f3c16a9e3b55774.1787205067.git.sam@gentoo.org> From: Aldy Hernandez Date: Mon, 17 Aug 2026 14:53:24 +0000 Subject: [PATCH] path solver: only compute ranges at the current path position [PR126876] Since r17-3298 the path ranger can become the current query while fold_using_range folds a statement, so match.pd simplifications can query with a context statement that can be from an arbitrary block on the path. The solver's positional machinery is only meaningful at the block the walk is currently at. Only compute ranges at the current path position otherwise fall back to the global range. Assert the positional invariant in range_defined_in_block, which I verified holds by testing the assert on a tree before r17-3298. Tested on ppc64le Linux. PR tree-optimization/126876 gcc/ChangeLog: * gimple-range-path.cc (path_range_query::internal_range_of_expr): Only call range_defined_in_block at the current path position. (path_range_query::range_defined_in_block): Assert the current path position. --- gcc/gimple-range-path.cc | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/gcc/gimple-range-path.cc b/gcc/gimple-range-path.cc index 467e321b8ded..54c8a04b486f 100644 --- a/gcc/gimple-range-path.cc +++ b/gcc/gimple-range-path.cc @@ -156,7 +156,12 @@ path_range_query::internal_range_of_expr (vrange &r, tree name, gimple *stmt) return true; } + // We can be called from match.pd or elsewhere, with a context statement + // that can be anywhere on the path. Since we can only compute ranges + // mid flight at the current path position, check that's the case, + // otherwise fall through to the global range. if (stmt + && gimple_bb (stmt) == curr_bb () && range_defined_in_block (r, name, gimple_bb (stmt))) { if (TREE_CODE (name) == SSA_NAME) @@ -290,6 +295,11 @@ path_range_query::ssa_range_in_phi (vrange &r, gphi *phi) bool path_range_query::range_defined_in_block (vrange &r, tree name, basic_block bb) { + // Ranges can only be calculated at the current path position, both + // while pre-computing the cache and when answering questions at the + // path exit afterwards. + gcc_assert (bb == curr_bb ()); + gimple *def_stmt = SSA_NAME_DEF_STMT (name); basic_block def_bb = gimple_bb (def_stmt); -- 2.55.0