[Bug tree-optimization/46590] long compile time with -O2 and many loops

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46590

--- Comment #51 from Richard Biener <rguenth at gcc dot gnu.org> ---
Alternative patch, the first one doesn't seem to work (probably
all_blocks is sometimes NULL, will debug).

Index: gcc/df.h
===================================================================
--- gcc/df.h    (revision 270053)
+++ gcc/df.h    (working copy)
@@ -1023,6 +1023,7 @@ extern void df_lr_verify_transfer_functi
 extern void df_live_verify_transfer_functions (void);
 extern void df_live_add_problem (void);
 extern void df_live_set_all_dirty (void);
+extern void df_live_set_loop_dirty (struct loop *);
 extern void df_chain_add_problem (unsigned int);
 extern void df_word_lr_add_problem (void);
 extern bool df_word_lr_mark_ref (df_ref, bool, bitmap);
Index: gcc/df-problems.c
===================================================================
--- gcc/df-problems.c   (revision 270053)
+++ gcc/df-problems.c   (working copy)
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3.
 #include "valtrack.h"
 #include "dumpfile.h"
 #include "rtl-iter.h"
+#include "cfgloop.h"

 /* Note that turning REG_DEAD_DEBUGGING on will cause
    gcc.c-torture/unsorted/dump-noaddr.c to fail because it prints
@@ -1774,6 +1775,18 @@ df_live_set_all_dirty (void)
 }


+/* Set all of the blocks of LOOP as dirty.  This needs to be done if this
+   problem is added after all of the insns have been scanned.  */
+
+void
+df_live_set_loop_dirty (struct loop *loop)
+{
+  basic_block *bbs = get_loop_body (loop);
+  for (unsigned i = 0; i < loop->num_nodes; ++i)
+    bitmap_set_bit (df_live->out_of_date_transfer_functions, bbs[i]->index);
+}
+
+
 /* Verify that all of the lr related info is consistent and
    correct.  */

Index: gcc/loop-invariant.c
===================================================================
--- gcc/loop-invariant.c        (revision 270053)
+++ gcc/loop-invariant.c        (working copy)
@@ -685,7 +685,7 @@ find_defs (struct loop *loop)
   df_process_deferred_rescans ();
   df_chain_add_problem (DF_UD_CHAIN);
   df_live_add_problem ();
-  df_live_set_all_dirty ();
+  df_live_set_loop_dirty (loop);
   df_set_flags (DF_RD_PRUNE_DEAD_DEFS);
   df_analyze_loop (loop);
   check_invariant_table_size ();