From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1075) id F0E5B3858417; Mon, 23 Aug 2021 07:22:29 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F0E5B3858417 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jan Hubicka To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-3064] Improve return slot handling in ipa-modref X-Act-Checkin: gcc X-Git-Author: Jan Hubicka X-Git-Refname: refs/heads/master X-Git-Oldrev: f93f0868919ab32bfbc24adb40158298031a4d58 X-Git-Newrev: 59f38935d189027f172b4813a6056addaceb7cd3 Message-Id: <20210823072229.F0E5B3858417@sourceware.org> Date: Mon, 23 Aug 2021 07:22:29 +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: Mon, 23 Aug 2021 07:22:30 -0000 https://gcc.gnu.org/g:59f38935d189027f172b4813a6056addaceb7cd3 commit r12-3064-g59f38935d189027f172b4813a6056addaceb7cd3 Author: Jan Hubicka Date: Mon Aug 23 09:21:36 2021 +0200 Improve return slot handling in ipa-modref gcc/ChangeLog: * ipa-modref.c (analyze_ssa_name_flags): Improve handling of return slot. gcc/testsuite/ChangeLog: * g++.dg/tree-ssa/modref-1.C: New test. Diff: --- gcc/ipa-modref.c | 23 ++++++++++------------- gcc/testsuite/g++.dg/tree-ssa/modref-1.C | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+), 13 deletions(-) diff --git a/gcc/ipa-modref.c b/gcc/ipa-modref.c index 549153865b8..cb0a314cbeb 100644 --- a/gcc/ipa-modref.c +++ b/gcc/ipa-modref.c @@ -1709,19 +1709,8 @@ analyze_ssa_name_flags (tree name, vec &lattice, int depth, if (gimple_call_fn (use_stmt) == name) lattice[index].merge (~EAF_NOCLOBBER); - /* Return slot optimization would require bit of propagation; - give up for now. */ - if (gimple_call_return_slot_opt_p (call) - && gimple_call_lhs (call) != NULL_TREE - && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (call)))) - { - if (dump_file) - fprintf (dump_file, "%*s Unhandled return slot opt\n", - depth * 4, ""); - lattice[index].merge (0); - } /* Recursion would require bit of propagation; give up for now. */ - else if (callee && !ipa && recursive_call_p (current_function_decl, + if (callee && !ipa && recursive_call_p (current_function_decl, callee)) lattice[index].merge (0); else @@ -1735,7 +1724,15 @@ analyze_ssa_name_flags (tree name, vec &lattice, int depth, /* Handle *name = func (...). */ if (gimple_call_lhs (call) && memory_access_to (gimple_call_lhs (call), name)) - lattice[index].merge_direct_store (); + { + lattice[index].merge_direct_store (); + /* Return slot optimization passes address of + LHS to callee via hidden parameter and this + may make LHS to escape. See PR 98499. */ + if (gimple_call_return_slot_opt_p (call) + && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (call)))) + lattice[index].merge (EAF_NOREAD | EAF_DIRECT); + } /* We do not track accesses to the static chain (we could) so give up. */ diff --git a/gcc/testsuite/g++.dg/tree-ssa/modref-1.C b/gcc/testsuite/g++.dg/tree-ssa/modref-1.C new file mode 100644 index 00000000000..c742dfe8b33 --- /dev/null +++ b/gcc/testsuite/g++.dg/tree-ssa/modref-1.C @@ -0,0 +1,32 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ +struct S { int a; char b[20]; S(); S(S const&); }; +volatile int global; + +__attribute__ ((noinline,noclone)) +struct S noescape (int *b) +{ + struct S a; + a.a = b!=0; + global = 1; + return a; +} + +void escape (struct S *p); + +__attribute__ ((noinline,noclone)) +int +test(int *b) +{ + struct S s = noescape (b); + escape (&s); + return *b; +} +int test2() +{ + int b=1234; + test (&b); + return b; +} +// ipa-modref should analyze parameter B of test as noescape. +// { dg-final { scan-tree-dump "return 1234" } }