From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1059) id E555738708B7; Thu, 27 Aug 2020 18:08:25 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E555738708B7 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1598551705; bh=6b5+YLJmaNNc1vAaKtuJou99QZfZq+vckJ+Qlvl+wu8=; h=From:To:Subject:Date:From; b=dSHySRIbNJNmxiUueH2tezkmlfO0Y/CB+x2qZwJgsfCMMicR8/+T3SFKg3W8J7+AL /4PvqfY6wLkBc6XpNcxJJSm71gWC13ubWm9FibUndnHVlw90oPTfG5pJ5T/qdnjEJv E786gGsIOf+TVhM7HPG17nVq65HOw1/caNKu7CJg= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Nathan Sidwell To: gcc-cvs@gcc.gnu.org Subject: [gcc/devel/c++-modules] ipa: fix bit CPP when combined with IPA bit CP X-Act-Checkin: gcc X-Git-Author: Martin Liska X-Git-Refname: refs/heads/devel/c++-modules X-Git-Oldrev: b418ccb358e428091fb9c6020fd10be5ae40a17a X-Git-Newrev: d58f078ce2d53e5dab6b3d0d5f960504268e1894 Message-Id: <20200827180825.E555738708B7@sourceware.org> Date: Thu, 27 Aug 2020 18:08:25 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Aug 2020 18:08:26 -0000 https://gcc.gnu.org/g:d58f078ce2d53e5dab6b3d0d5f960504268e1894 commit d58f078ce2d53e5dab6b3d0d5f960504268e1894 Author: Martin Liska Date: Wed Aug 12 09:21:51 2020 +0200 ipa: fix bit CPP when combined with IPA bit CP As mentioned in the PR, let's consider the following example: int __attribute__((noinline)) foo(int arg) { if (arg == 3) return 1; if (arg == 4) return 123; __builtin_unreachable (); } during WPA we find all calls of the function (yes the call with value 5 is UBSAN): Node: foo/0: param [0]: 5 [loc_time: 4, loc_size: 2, prop_time: 0, prop_size: 0] 3 [loc_time: 3, loc_size: 3, prop_time: 0, prop_size: 0] ctxs: VARIABLE Bits: value = 0x5, mask = 0x6 in LTRANS we have the following VRP info: # RANGE [3, 3] NONZERO 3 when we AND masks in get_default_value we end up with 6 & 3 = 2 (0x010). That means the only second (least significant bit) is unknown and value (5 = 0x101) & ~mask gives us either 7 (0x111) or 5 (0x101). That's why if (arg_2(D) == 3) gets optimized to false. gcc/ChangeLog: PR ipa/96482 * ipa-cp.c (ipcp_bits_lattice::meet_with_1): Drop value bits for bits that are unknown. (ipcp_bits_lattice::set_to_constant): Likewise. * tree-ssa-ccp.c (get_default_value): Add sanity check that IPA CP bit info has all bits set to zero in bits that are unknown. gcc/testsuite/ChangeLog: PR ipa/96482 * gcc.dg/ipa/pr96482.c: New test. Diff: --- gcc/ipa-cp.c | 3 ++- gcc/testsuite/gcc.dg/ipa/pr96482.c | 44 ++++++++++++++++++++++++++++++++++++++ gcc/tree-ssa-ccp.c | 3 +++ 3 files changed, 49 insertions(+), 1 deletion(-) diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c index 945a69977f3..2b21280d919 100644 --- a/gcc/ipa-cp.c +++ b/gcc/ipa-cp.c @@ -1011,7 +1011,7 @@ ipcp_bits_lattice::set_to_constant (widest_int value, widest_int mask) { gcc_assert (top_p ()); m_lattice_val = IPA_BITS_CONSTANT; - m_value = value; + m_value = wi::bit_and (wi::bit_not (mask), value); m_mask = mask; return true; } @@ -1048,6 +1048,7 @@ ipcp_bits_lattice::meet_with_1 (widest_int value, widest_int mask, widest_int old_mask = m_mask; m_mask = (m_mask | mask) | (m_value ^ value); + m_value &= value; if (wi::sext (m_mask, precision) == -1) return set_to_bottom (); diff --git a/gcc/testsuite/gcc.dg/ipa/pr96482.c b/gcc/testsuite/gcc.dg/ipa/pr96482.c new file mode 100644 index 00000000000..68ead798d28 --- /dev/null +++ b/gcc/testsuite/gcc.dg/ipa/pr96482.c @@ -0,0 +1,44 @@ +/* PR ipa/96482 */ +/* { dg-do run } */ +/* { dg-options "-O2 -flto" } */ +/* { dg-require-effective-target lto } */ + +int +__attribute__((noinline)) +foo(int arg) +{ + if (arg == 3) + return 1; + if (arg == 4) + return 123; + + __builtin_unreachable (); +} + +int +__attribute__((noinline)) +baz(int x) +{ + if (x != 0) + return foo(3); /* called */ + + return 1; +} + +int +__attribute__((noinline)) +bar(int x) +{ + if (x == 0) + return foo(5); /* not executed */ + + return 1; +} + +int main(int argc, char **argv) +{ + if (bar(argc) != baz(argc)) + __builtin_abort (); + + return 0; +} diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c index 7e3921869b8..65dffe06530 100644 --- a/gcc/tree-ssa-ccp.c +++ b/gcc/tree-ssa-ccp.c @@ -306,6 +306,9 @@ get_default_value (tree var) { val.lattice_val = CONSTANT; val.value = value; + widest_int ipa_value = wi::to_widest (value); + /* Unknown bits from IPA CP must be equal to zero. */ + gcc_assert (wi::bit_and (ipa_value, mask) == 0); val.mask = mask; if (nonzero_bits != -1) val.mask &= extend_mask (nonzero_bits,