Message ID | 20180221190928.GA23794@kam.mff.cuni.cz |
---|---|
State | New |
Headers | show |
Series | PR84229 part 1: Avoid cloning of functions that calls va_arg_pack | expand |
On Wed, Feb 21, 2018 at 08:09:28PM +0100, Jan Hubicka wrote: > --- ipa-cp.c (revision 257844) > +++ ipa-cp.c (working copy) > @@ -630,6 +630,24 @@ determine_versionability (struct cgraph_ > reason = "calls comdat-local function"; > } > > + /* Functions calling BUILT_IN_VA_ARG_PACK and BUILT_IN_VA_ARG_PACK_LEN > + works only when inlined. Cloning them may still lead to better code s/works/work/ > + becuase ipa-cp will not give up on cloning further. If the function is s/becuase/because/ > + external this however leads to wrong code becuase we may end up producing s/becuase/because/ > + offline copy of the function. */ > + if (DECL_EXTERNAL (node->decl)) > + for (cgraph_edge *edge = node->callees; !reason && edge; > + edge = edge->next_callee) > + if (DECL_BUILT_IN (edge->callee->decl) > + && DECL_BUILT_IN_CLASS (edge->callee->decl) == BUILT_IN_NORMAL) > + { > + if (DECL_FUNCTION_CODE (edge->callee->decl) == BUILT_IN_VA_ARG_PACK) > + reason = "external function which calls va_arg_pack"; > + if (DECL_FUNCTION_CODE (edge->callee->decl) > + == BUILT_IN_VA_ARG_PACK_LEN) > + reason = "external function which calls va_arg_pack_len"; > + } > + > if (reason && dump_file && !node->alias && !node->thunk.thunk_p) > fprintf (dump_file, "Function %s is not versionable, reason: %s.\n", > node->dump_name (), reason); Do you have a testcase for this, or is it LTO with too large input? Jakub
> On Wed, Feb 21, 2018 at 08:09:28PM +0100, Jan Hubicka wrote: > > --- ipa-cp.c (revision 257844) > > +++ ipa-cp.c (working copy) > > @@ -630,6 +630,24 @@ determine_versionability (struct cgraph_ > > reason = "calls comdat-local function"; > > } > > > > + /* Functions calling BUILT_IN_VA_ARG_PACK and BUILT_IN_VA_ARG_PACK_LEN > > + works only when inlined. Cloning them may still lead to better code > > s/works/work/ > > > + becuase ipa-cp will not give up on cloning further. If the function is > > s/becuase/because/ > > > + external this however leads to wrong code becuase we may end up producing > > s/becuase/because/ Thanks, fixed. > > > + offline copy of the function. */ > > + if (DECL_EXTERNAL (node->decl)) > > + for (cgraph_edge *edge = node->callees; !reason && edge; > > + edge = edge->next_callee) > > + if (DECL_BUILT_IN (edge->callee->decl) > > + && DECL_BUILT_IN_CLASS (edge->callee->decl) == BUILT_IN_NORMAL) > > + { > > + if (DECL_FUNCTION_CODE (edge->callee->decl) == BUILT_IN_VA_ARG_PACK) > > + reason = "external function which calls va_arg_pack"; > > + if (DECL_FUNCTION_CODE (edge->callee->decl) > > + == BUILT_IN_VA_ARG_PACK_LEN) > > + reason = "external function which calls va_arg_pack_len"; > > + } > > + > > if (reason && dump_file && !node->alias && !node->thunk.thunk_p) > > fprintf (dump_file, "Function %s is not versionable, reason: %s.\n", > > node->dump_name (), reason); > > Do you have a testcase for this, or is it LTO with too large input? There is reduced testcase in the PR which probably should be rejected by C frontend because it is uses va_arg_pack on non-variadic function. I plan to send additional patches and then come with a testcase (because current one should be early inlined and thus it will stop testing ipa-cp) Honza
Index: ipa-cp.c =================================================================== --- ipa-cp.c (revision 257844) +++ ipa-cp.c (working copy) @@ -630,6 +630,24 @@ determine_versionability (struct cgraph_ reason = "calls comdat-local function"; } + /* Functions calling BUILT_IN_VA_ARG_PACK and BUILT_IN_VA_ARG_PACK_LEN + works only when inlined. Cloning them may still lead to better code + becuase ipa-cp will not give up on cloning further. If the function is + external this however leads to wrong code becuase we may end up producing + offline copy of the function. */ + if (DECL_EXTERNAL (node->decl)) + for (cgraph_edge *edge = node->callees; !reason && edge; + edge = edge->next_callee) + if (DECL_BUILT_IN (edge->callee->decl) + && DECL_BUILT_IN_CLASS (edge->callee->decl) == BUILT_IN_NORMAL) + { + if (DECL_FUNCTION_CODE (edge->callee->decl) == BUILT_IN_VA_ARG_PACK) + reason = "external function which calls va_arg_pack"; + if (DECL_FUNCTION_CODE (edge->callee->decl) + == BUILT_IN_VA_ARG_PACK_LEN) + reason = "external function which calls va_arg_pack_len"; + } + if (reason && dump_file && !node->alias && !node->thunk.thunk_p) fprintf (dump_file, "Function %s is not versionable, reason: %s.\n", node->dump_name (), reason);