ipa-inline: Add target info into fn summary [PR102059]

Power ISA 2.07 (Power8) introduces transactional memory
feature but ISA3.1 (Power10) removes it.  It exposes one
troublesome issue as PR102059 shows.  Users define some
function with target pragma cpu=power10 then it calls one
function with attribute always_inline which inherits
command line option -mcpu=power8 which enables HTM
implicitly.  The current isa_flags check doesn't allow this
inlining due to "target specific option mismatch" and error
mesasge is emitted.

Normally, the callee function isn't intended to exploit HTM
feature, but the default flag setting make it look it has.
As Richi raised in the PR, we have fp_expressions flag in
function summary, and allow us to check the function
actually contains any floating point expressions to avoid
overkill.  So this patch follows the similar idea but is
more target specific, for this rs6000 port specific
requirement on HTM feature check, we would like to check
rs6000 specific HTM built-in functions and inline assembly,
it allows targets to do their own customized checks and
updates.

It introduces two target hooks need_ipa_fn_target_info and
update_ipa_fn_target_info.  The former allows target to do
some previous check and decides to collect target specific
information for this function or not.  For some special
case, it can predict the analysis result and set it early
without any scannings.  The latter allows the
analyze_function_body to pass gimple stmts down just like
fp_expressions handlings, target can do its own tricks.
I put them together as one hook initially with one boolean
to indicate whether it's initial time, but the code looks a
bit ugly, to separate them seems to have better readability.

gcc/ChangeLog:

	PR ipa/102059
	* config/rs6000/rs6000.c (TARGET_NEED_IPA_FN_TARGET_INFO): New macro.
	(TARGET_UPDATE_IPA_FN_TARGET_INFO): Likewise.
	(rs6000_need_ipa_fn_target_info): New function.
	(rs6000_update_ipa_fn_target_info): Likewise.
	(rs6000_can_inline_p): Adjust for ipa function summary target info.
	* config/rs6000/rs6000.h (RS6000_FN_TARGET_INFO_HTM): New macro.
	* ipa-fnsummary.c (ipa_dump_fn_summary): Adjust for ipa function
	summary target info.
	(analyze_function_body): Adjust for ipa function summary target info
	and call hook rs6000_need_ipa_fn_target_info and
	rs6000_update_ipa_fn_target_info.
	(ipa_merge_fn_summary_after_inlining): Adjust for ipa function summary
	target info.
	(inline_read_section): Likewise.
	(ipa_fn_summary_write): Likewise.
	* ipa-fnsummary.h (ipa_fn_summary::target_info): New member.
	* doc/tm.texi: Regenerate.
	* doc/tm.texi.in (TARGET_UPDATE_IPA_FN_TARGET_INFO): Document new hook.
	(TARGET_NEED_IPA_FN_TARGET_INFO): Likewise.
	* target.def (update_ipa_fn_target_info): New hook.
	(need_ipa_fn_target_info): Likewise.
	* targhooks.c (default_need_ipa_fn_target_info): New function.
	(default_update_ipa_fn_target_info): Likewise.
	* targhooks.h (default_update_ipa_fn_target_info): New declare.
	(default_need_ipa_fn_target_info): Likewise.

gcc/testsuite/ChangeLog:

	PR ipa/102059
	* gcc.dg/lto/pr102059-1_0.c: New test.
	* gcc.dg/lto/pr102059-1_1.c: New test.
	* gcc.dg/lto/pr102059-1_2.c: New test.
	* gcc.dg/lto/pr102059-2_0.c: New test.
	* gcc.dg/lto/pr102059-2_1.c: New test.
	* gcc.dg/lto/pr102059-2_2.c: New test.
	* gcc.target/powerpc/pr102059-1.c: New test.
	* gcc.target/powerpc/pr102059-2.c: New test.
	* gcc.target/powerpc/pr102059-3.c: New test.

1 files changed, 35 insertions, 0 deletions

diff --git a/gcc/target.def b/gcc/target.def
index 6a6d621..8fd2533 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -6536,6 +6536,41 @@ specific target options and the caller does not use the same options.",
  default_target_can_inline_p)
 
 DEFHOOK
+(update_ipa_fn_target_info,
+ "Allow target to analyze all gimple statements for the given function to\n\
+record and update some target specific information for inlining.  A typical\n\
+example is that a caller with one isa feature disabled is normally not\n\
+allowed to inline a callee with that same isa feature enabled even which is\n\
+attributed by always_inline, but with the conservative analysis on all\n\
+statements of the callee if we are able to guarantee the callee does not\n\
+exploit any instructions from the mismatch isa feature, it would be safe to\n\
+allow the caller to inline the callee.\n\
+@var{info} is one @code{unsigned int} value to record information in which\n\
+one set bit indicates one corresponding feature is detected in the analysis,\n\
+@var{stmt} is the statement being analyzed.  Return true if target still\n\
+need to analyze the subsequent statements, otherwise return false to stop\n\
+subsequent analysis.\n\
+The default version of this hook returns false.",
+ bool, (unsigned int& info, const gimple* stmt),
+ default_update_ipa_fn_target_info)
+
+DEFHOOK
+(need_ipa_fn_target_info,
+ "Allow target to check early whether it is necessary to analyze all gimple\n\
+statements in the given function to update target specific information for\n\
+inlining.  See hook @code{update_ipa_fn_target_info} for usage example of\n\
+target specific information.  This hook is expected to be invoked ahead of\n\
+the iterating with hook @code{update_ipa_fn_target_info}.\n\
+@var{decl} is the function being analyzed, @var{info} is the same as what\n\
+in hook @code{update_ipa_fn_target_info}, target can do one time update\n\
+into @var{info} without iterating for some case.  Return true if target\n\
+decides to analyze all gimple statements to collect information, otherwise\n\
+return false.\n\
+The default version of this hook returns false.",
+ bool, (const_tree decl, unsigned int& info),
+ default_need_ipa_fn_target_info)
+
+DEFHOOK
 (relayout_function,
 "This target hook fixes function @var{fndecl} after attributes are processed.\n\
 Default does nothing. On ARM, the default function's alignment is updated\n\