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[PATCH] Fix PR52808
- From: Richard Guenther <rguenther at suse dot de>
- To: gcc-patches at gcc dot gnu dot org
- Date: Wed, 4 Apr 2012 12:48:28 +0200 (CEST)
- Subject: [PATCH] Fix PR52808
This fixes LTO profiledbootstrap. tracer tail-duplicates loop
headers; that is not profitable and it makes loops have multiple
entries which inhibits further optimization. The following
patch cures that.
LTO profiledbootstrapped on x86_64-unknown-linux-gnu, regular
testing in progress.
Richard.
2012-04-04 Richard Guenther <rguenther@suse.de>
PR tree-optimization/52808
* tracer.c (tail_duplicate): Do not tail-duplicate loop header
blocks.
* Makefile.in (tracer.o): Depend on $(CFGLOOP_H).
Index: gcc/tracer.c
===================================================================
*** gcc/tracer.c (revision 186134)
--- gcc/tracer.c (working copy)
***************
*** 52,57 ****
--- 52,58 ----
#include "tree-pass.h"
#include "tree-flow.h"
#include "tree-inline.h"
+ #include "cfgloop.h"
static int count_insns (basic_block);
static bool ignore_bb_p (const_basic_block);
*************** tail_duplicate (void)
*** 307,313 ****
}
traced_insns += bb2->frequency * counts [bb2->index];
if (EDGE_COUNT (bb2->preds) > 1
! && can_duplicate_block_p (bb2))
{
edge e;
basic_block copy;
--- 308,320 ----
}
traced_insns += bb2->frequency * counts [bb2->index];
if (EDGE_COUNT (bb2->preds) > 1
! && can_duplicate_block_p (bb2)
! /* We have the tendency to duplicate the loop header
! of all do { } while loops. Do not do that - it is
! not profitable and it might create a loop with multiple
! entries or at least rotate the loop. */
! && (!current_loops
! || bb2->loop_father->header != bb2))
{
edge e;
basic_block copy;
Index: gcc/Makefile.in
===================================================================
--- gcc/Makefile.in (revision 186134)
+++ gcc/Makefile.in (working copy)
@@ -3391,7 +3391,7 @@ bb-reorder.o : bb-reorder.c $(CONFIG_H)
tracer.o : tracer.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
$(TREE_H) $(BASIC_BLOCK_H) hard-reg-set.h output.h $(CFGLAYOUT_H) \
$(FLAGS_H) $(TIMEVAR_H) $(PARAMS_H) $(COVERAGE_H) $(FIBHEAP_H) \
- $(TREE_PASS_H) $(TREE_FLOW_H) $(TREE_INLINE_H)
+ $(TREE_PASS_H) $(TREE_FLOW_H) $(TREE_INLINE_H) $(CFGLOOP_H)
cfglayout.o : cfglayout.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
$(RTL_H) $(TREE_H) insn-config.h $(BASIC_BLOCK_H) hard-reg-set.h output.h \
$(FUNCTION_H) $(CFGLAYOUT_H) $(CFGLOOP_H) $(TARGET_H) gt-cfglayout.h \