Introduce 4-stages profiledbootstrap to get a better profile.

2017-06-19  Martin Liska  <mliska@suse.cz>

	* doc/install.texi: Document that PGO runs in 4 stages.
2017-06-19  Martin Liska  <mliska@suse.cz>

	* Makefile.def: Define 4 stages PGO bootstrap.
	* Makefile.tpl: Define FLAGS.
	* Makefile.in: Regenerate.

From-SVN: r249366

ChangeLog

+2017-06-19  Martin Liska  <mliska@suse.cz>
+
+	* Makefile.def: Define 4 stages PGO bootstrap.
+	* Makefile.tpl: Define FLAGS.
+	* Makefile.in: Regenerate.
+
 2017-06-14  Ian Lance Taylor  <iant@golang.org>
 
 	* Makefile.def: Add check-gotools to go check targets.

Makefile.def

@@ -623,7 +623,10 @@ bootstrap_stage = {
 bootstrap_stage = {
 	id=profile ; prev=1 ; };
 bootstrap_stage = {
-	id=feedback ; prev=profile ;
+	id=train; prev=profile ;
+	bootstrap_target=profiledbootstrap ; };
+bootstrap_stage = {
+	id=feedback ; prev=train;
 	bootstrap_target=profiledbootstrap ; };
 bootstrap_stage = {
 	id=autoprofile ; prev=1 ;

Makefile.tpl

@@ -455,8 +455,11 @@ STAGE1_CONFIGURE_FLAGS = --disable-intermodule $(STAGE1_CHECKING) \
 STAGEprofile_CFLAGS = $(STAGE2_CFLAGS) -fprofile-generate
 STAGEprofile_TFLAGS = $(STAGE2_TFLAGS)
 
-STAGEfeedback_CFLAGS = $(STAGE3_CFLAGS) -fprofile-use
-STAGEfeedback_TFLAGS = $(STAGE3_TFLAGS)
+STAGEtrain_CFLAGS = $(STAGE3_CFLAGS)
+STAGEtrain_TFLAGS = $(STAGE3_TFLAGS)
+
+STAGEfeedback_CFLAGS = $(STAGE4_CFLAGS) -fprofile-use
+STAGEfeedback_TFLAGS = $(STAGE4_TFLAGS)
 
 STAGEautoprofile_CFLAGS = $(STAGE2_CFLAGS) -g
 STAGEautoprofile_TFLAGS = $(STAGE2_TFLAGS)

gcc/ChangeLog

 2017-06-19  Martin Liska  <mliska@suse.cz>
 
+	* doc/install.texi: Document that PGO runs in 4 stages.
+
+2017-06-19  Martin Liska  <mliska@suse.cz>
+
 	PR ipa/80732
 	* attribs.c (make_dispatcher_decl): Do not append '.ifunc'
 	to dispatcher function name.

gcc/doc/install.texi

@@ -2619,8 +2619,9 @@ bootstrap the compiler with profile feedback, use @code{make profiledbootstrap}.
 When @samp{make profiledbootstrap} is run, it will first build a @code{stage1}
 compiler.  This compiler is used to build a @code{stageprofile} compiler
 instrumented to collect execution counts of instruction and branch
-probabilities.  Then runtime libraries are compiled with profile collected.
-Finally a @code{stagefeedback} compiler is built using the information collected.
+probabilities.  Training run is done by building @code{stagetrain}
+compiler.  Finally a @code{stagefeedback} compiler is built
+using the information collected.
 
 Unlike standard bootstrap, several additional restrictions apply.  The
 compiler used to build @code{stage1} needs to support a 64-bit integral type.