From c952126870c92cf293d59ffb1497e402eb8fc269 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Tue, 18 Jan 2022 13:48:34 +0100 Subject: [PATCH] ipa/103989 - avoid IPA inlining of small functions with -Og The following change avoids doing IPA inlining of small functions into functions compiled with -Og - those functions will see almost no followup scalar cleanups so that the benefit anticipated by the inliner will not be realized and instead the late diagnostic code will be confused by dead code that is left around. 2022-01-18 Richard Biener PR ipa/103989 * ipa-inline.cc (inline_small_functions): Do not enqueue call edges originating in functions compiled with -Og. * g++.dg/opt/pr103989.C: New testcase. --- gcc/ipa-inline.cc | 7 ++++++- gcc/testsuite/g++.dg/opt/pr103989.C | 30 ++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/opt/pr103989.C diff --git a/gcc/ipa-inline.cc b/gcc/ipa-inline.cc index 3852277..f8bb072 100644 --- a/gcc/ipa-inline.cc +++ b/gcc/ipa-inline.cc @@ -2029,7 +2029,12 @@ inline_small_functions (void) struct cgraph_edge *next = NULL; bool has_speculative = false; - if (!opt_for_fn (node->decl, optimize)) + if (!opt_for_fn (node->decl, optimize) + /* With -Og we do not want to perform IPA inlining of small + functions since there are no scalar cleanups after it + that would realize the anticipated win. All abstraction + is removed during early inlining. */ + || opt_for_fn (node->decl, optimize_debug)) continue; if (dump_file) diff --git a/gcc/testsuite/g++.dg/opt/pr103989.C b/gcc/testsuite/g++.dg/opt/pr103989.C new file mode 100644 index 0000000..4604811 --- /dev/null +++ b/gcc/testsuite/g++.dg/opt/pr103989.C @@ -0,0 +1,30 @@ +// { dg-require-effective-target c++17 } +// { dg-options "-Og -Wall" } + +#include +#include + +struct A { + A (int a) : a {a} + {} + + const std::shared_ptr x; + int a; +}; + +class B +{ +public: + B (const std::optional & a) + : a {a} + { + } +public: + const std::optional a; +}; + +int +main () +{ + B b {std::nullopt}; +} -- 2.7.4