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From: Richard Biener <rguenth@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r14-9029] tree-optimization/113895 - consistency check fails in copy_reference_ops_from_ref Date: Fri, 16 Feb 2024 11:52:29 +0000 (GMT) [thread overview] Message-ID: <20240216115229.B47CD3858295@sourceware.org> (raw) https://gcc.gnu.org/g:5fd1cbfd65ef2b6dd87cd78ce6509e7d561981ac commit r14-9029-g5fd1cbfd65ef2b6dd87cd78ce6509e7d561981ac Author: Richard Biener <rguenther@suse.de> Date: Fri Feb 16 10:08:43 2024 +0100 tree-optimization/113895 - consistency check fails in copy_reference_ops_from_ref The following addresses consistency check fails in copy_reference_ops_from_ref when we are handling out-of-bound array accesses (it's almost impossible to identically mimic the get_ref_base_and_extent behavior). It also addresses the case where an out-of-bound constant offset computes to a -1 off which is the special value for "unknown". This patch basically turns off verification in those cases. PR tree-optimization/113895 * tree-ssa-sccvn.cc (copy_reference_ops_from_ref): Disable consistency checking when there are out-of-bound array accesses. Allow -1 off when from an array reference with constant index. * gcc.dg/torture/pr113895-2.c: New testcase. * gcc.dg/torture/pr113895-3.c: Likewise. * gcc.dg/torture/pr113895-4.c: Likewise. Diff: --- gcc/testsuite/gcc.dg/torture/pr113895-2.c | 13 +++++++++++++ gcc/testsuite/gcc.dg/torture/pr113895-3.c | 10 ++++++++++ gcc/testsuite/gcc.dg/torture/pr113895-4.c | 14 ++++++++++++++ gcc/tree-ssa-sccvn.cc | 31 +++++++++++++++++++++++++++++-- 4 files changed, 66 insertions(+), 2 deletions(-) diff --git a/gcc/testsuite/gcc.dg/torture/pr113895-2.c b/gcc/testsuite/gcc.dg/torture/pr113895-2.c new file mode 100644 index 000000000000..a1c20250c99c --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr113895-2.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ + +extern void d(int); +int a[2][4], b; +int main() { + while (b) { + int c; + d(a[b][c]); + for (c = 0; c < 7; c++) + ; + } + return 0; +} diff --git a/gcc/testsuite/gcc.dg/torture/pr113895-3.c b/gcc/testsuite/gcc.dg/torture/pr113895-3.c new file mode 100644 index 000000000000..255975f3353f --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr113895-3.c @@ -0,0 +1,10 @@ +/* { dg-do compile } */ + +extern void f(); +char a[1][1], b; +int main() { + int c = -1U; + if (b) + f(a[c][b]); + return 0; +} diff --git a/gcc/testsuite/gcc.dg/torture/pr113895-4.c b/gcc/testsuite/gcc.dg/torture/pr113895-4.c new file mode 100644 index 000000000000..75f71dcb451a --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr113895-4.c @@ -0,0 +1,14 @@ +/* { dg-do compile } */ + +long a, b, c; +int d; +long e[2][1]; +int f() { + if (c == a) + c = b; +} +void g() { + int h, i = 0; + for (; f() + d + i; i++) + e[h][i] = 4; +} diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc index d6b8c734e7ba..38b806649cd9 100644 --- a/gcc/tree-ssa-sccvn.cc +++ b/gcc/tree-ssa-sccvn.cc @@ -1107,9 +1107,29 @@ copy_reference_ops_from_ref (tree ref, vec<vn_reference_op_s> *result) the vn_reference ops differ by adjusting those indexes to appropriate constants. */ poly_int64 off = 0; + bool oob_index = false; for (unsigned i = result->length (); i > start; --i) { auto &op = (*result)[i-1]; + if (flag_checking + && op.opcode == ARRAY_REF + && TREE_CODE (op.op0) == INTEGER_CST) + { + /* The verifier below chokes on inconsistencies of handling + out-of-bound accesses so disable it in that case. */ + tree atype = (*result)[i].type; + if (TREE_CODE (atype) == ARRAY_TYPE) + if (tree dom = TYPE_DOMAIN (atype)) + if ((TYPE_MIN_VALUE (dom) + && TREE_CODE (TYPE_MIN_VALUE (dom)) == INTEGER_CST + && (wi::to_widest (op.op0) + < wi::to_widest (TYPE_MIN_VALUE (dom)))) + || (TYPE_MAX_VALUE (dom) + && TREE_CODE (TYPE_MAX_VALUE (dom)) == INTEGER_CST + && (wi::to_widest (op.op0) + > wi::to_widest (TYPE_MAX_VALUE (dom))))) + oob_index = true; + } if ((op.opcode == ARRAY_REF || op.opcode == ARRAY_RANGE_REF) && TREE_CODE (op.op0) == SSA_NAME) @@ -1162,12 +1182,19 @@ copy_reference_ops_from_ref (tree ref, vec<vn_reference_op_s> *result) } else { - gcc_assert (known_ne (op.off, -1)); + gcc_assert (known_ne (op.off, -1) + /* Out-of-bound indices can compute to + a known -1 offset. */ + || ((op.opcode == ARRAY_REF + || op.opcode == ARRAY_RANGE_REF) + && poly_int_tree_p (op.op0) + && poly_int_tree_p (op.op1) + && TREE_CODE (op.op2) == INTEGER_CST)); off += op.off * BITS_PER_UNIT; } } } - if (flag_checking) + if (flag_checking && !oob_index) { ao_ref r; if (start != 0)
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