From 9cc8ca8da90426f625481195a2127a5e86689bcd Mon Sep 17 00:00:00 2001 From: Jan Hubicka Date: Fri, 5 Nov 2021 23:17:50 +0100 Subject: [PATCH] Avoid left shift of negative value in ipa-modref-tree.h gcc/ChangeLog: PR ipa/103082 * ipa-modref-tree.h (struct modref_access_node): Avoid left shift of negative value --- gcc/ipa-modref-tree.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/gcc/ipa-modref-tree.h b/gcc/ipa-modref-tree.h index 9976e489697e..bc428d193d24 100644 --- a/gcc/ipa-modref-tree.h +++ b/gcc/ipa-modref-tree.h @@ -116,8 +116,13 @@ struct GTY(()) modref_access_node if (!known_le (parm_offset, a.parm_offset) && !range_info_useful_p ()) return false; + /* We allow negative aoffset_adj here in case + there is an useful range. This is because adding + a.offset may result in non-ngative offset again. + Ubsan fails on val << LOG_BITS_PER_UNIT where val + is negative. */ aoffset_adj = (a.parm_offset - parm_offset) - << LOG2_BITS_PER_UNIT; + * BITS_PER_UNIT; } } if (range_info_useful_p ()) -- 2.47.2