Hi, Gentle ping https://gcc.gnu.org/pipermail/gcc-patches/2022-June/596212.html
BR, Kewen on 2022/6/6 14:20, Kewen.Lin via Gcc-patches wrote: > Hi, > > PR105459 exposes one issue in inline_call handling that when it > decides to copy FP flags from callee to caller and rebuild the > optimization node for caller fndecl, it's possible that the target > option node is also necessary to be rebuilt. Without updating > target option node early, it can make nodes share the same target > option node wrongly, later when we want to unshare it somewhere > (like in target hook) it can get unexpected results, like ICE on > uninitialized secondary member of target globals exposed in this PR. > > Commit r12-3721 makes it get exact fp_expression info and causes > more optimization chances then exposes this issue. Commit r11-5855 > introduces two target options to shadow flag_excess_precision and > flag_unsafe_math_optimizations and shows the need to rebuild target > node in inline_call when optimization node changes. > > As commented in PR105459, I tried to postpone init_function_start > in cgraph_node::expand, but abandoned it since I thought it just > concealed the issue. And I also tried to adjust the target node > when current function switching, but failed since we get the NULL > cfun and fndecl in WPA phase. > > Bootstrapped and regtested on x86_64-redhat-linux, powerpc64-linux-gnu > P8 and powerpc64le-linux-gnu P9. > > Any thoughts? Is it OK for trunk? > > BR, > Kewen > ----- > > PR tree-optimization/105459 > > gcc/ChangeLog: > > * ipa-inline-transform.cc (inline_call): Rebuild target option node > once optimization node gets rebuilt. > > gcc/testsuite/ChangeLog: > > * gcc.dg/lto/pr105459_0.c: New test. > --- > gcc/ipa-inline-transform.cc | 50 +++++++++++++++++++++++++-- > gcc/testsuite/gcc.dg/lto/pr105459_0.c | 35 +++++++++++++++++++ > 2 files changed, 83 insertions(+), 2 deletions(-) > create mode 100644 gcc/testsuite/gcc.dg/lto/pr105459_0.c > > diff --git a/gcc/ipa-inline-transform.cc b/gcc/ipa-inline-transform.cc > index 07288e57c73..edba58377f4 100644 > --- a/gcc/ipa-inline-transform.cc > +++ b/gcc/ipa-inline-transform.cc > @@ -52,6 +52,7 @@ along with GCC; see the file COPYING3. If not see > #include "ipa-modref.h" > #include "symtab-thunks.h" > #include "symtab-clones.h" > +#include "target.h" > > int ncalls_inlined; > int nfunctions_inlined; > @@ -469,8 +470,53 @@ inline_call (struct cgraph_edge *e, bool update_original, > } > > /* Reload global optimization flags. */ > - if (reload_optimization_node && DECL_STRUCT_FUNCTION (to->decl) == cfun) > - set_cfun (cfun, true); > + if (reload_optimization_node) > + { > + /* Only need to check and update target option node > + when target_option_default_node is not NULL. */ > + if (target_option_default_node) > + { > + /* Save the current context for optimization and target option > + node. */ > + tree old_optimize > + = build_optimization_node (&global_options, &global_options_set); > + tree old_target_opt > + = build_target_option_node (&global_options, &global_options_set); > + > + /* Restore optimization with new optimizatin node. */ > + tree new_optimize = DECL_FUNCTION_SPECIFIC_OPTIMIZATION (to->decl); > + if (old_optimize != new_optimize) > + cl_optimization_restore (&global_options, &global_options_set, > + TREE_OPTIMIZATION (new_optimize)); > + > + /* Restore target option with the one from caller fndecl. */ > + tree cur_target_opt = DECL_FUNCTION_SPECIFIC_TARGET (to->decl); > + if (!cur_target_opt) > + cur_target_opt = target_option_default_node; > + cl_target_option_restore (&global_options, &global_options_set, > + TREE_TARGET_OPTION (cur_target_opt)); > + > + /* Update target option as optimization changes. */ > + targetm.target_option.override (); > + > + /* Rebuild target option node for caller fndecl and replace > + with it if the node changes. */ > + tree new_target_opt > + = build_target_option_node (&global_options, &global_options_set); > + if (cur_target_opt != new_target_opt) > + DECL_FUNCTION_SPECIFIC_TARGET (to->decl) = new_target_opt; > + > + /* Restore the context with previous saved nodes. */ > + if (old_optimize != new_optimize) > + cl_optimization_restore (&global_options, &global_options_set, > + TREE_OPTIMIZATION (old_optimize)); > + cl_target_option_restore (&global_options, &global_options_set, > + TREE_TARGET_OPTION (old_target_opt)); > + } > + > + if (DECL_STRUCT_FUNCTION (to->decl) == cfun) > + set_cfun (cfun, true); > + } > > /* If aliases are involved, redirect edge to the actual destination and > possibly remove the aliases. */ > diff --git a/gcc/testsuite/gcc.dg/lto/pr105459_0.c > b/gcc/testsuite/gcc.dg/lto/pr105459_0.c > new file mode 100644 > index 00000000000..c799e6ef23d > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/lto/pr105459_0.c > @@ -0,0 +1,35 @@ > +/* { dg-lto-do link } */ > +/* { dg-lto-options { { -flto -O1 } } } */ > + > +double m; > +int n; > + > +__attribute__ ((optimize ("-funsafe-math-optimizations"))) > +void > +bar (int x) > +{ > + n = x; > + m = n; > +} > + > +__attribute__ ((flatten)) > +void > +foo (int x) > +{ > + bar (x); > +} > + > +void > +quux (void) > +{ > + ++n; > +} > + > +int > +main (void) > +{ > + foo (0); > + quux (); > + > + return 0; > +} > -- > 2.27.0