PR rtl-optimization/38711

	* ira.c (ira): Remove DF_LIVE if the problem is in the stack.
	(do_reload): Add it back at the end for -O2 and higher.

	* function.c (thread_prologue_and_epilogue_insns): Use
	REG_SET_TO_HARD_REG_SET instead of CLEAR_HARD_REG_SET and
	reg_set_to_hard_reg_set.



git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@192890 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 16 insertions, 0 deletions

diff --git a/gcc/ira.c b/gcc/ira.c
index 9a8b098cf48..8dcdbf57549 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -4399,6 +4399,16 @@ ira (FILE *f)
   setup_prohibited_mode_move_regs ();
 
   df_note_add_problem ();
+
+  /* DF_LIVE can't be used in the register allocator, too many other
+     parts of the compiler depend on using the "classic" liveness
+     interpretation of the DF_LR problem.  See PR38711.
+     Remove the problem, so that we don't spend time updating it in
+     any of the df_analyze() calls during IRA/LRA.  */
+  if (optimize > 1)
+    df_remove_problem (df_live);
+  gcc_checking_assert (df_live == NULL);
+
 #ifdef ENABLE_CHECKING
   df->changeable_flags |= DF_VERIFY_SCHEDULED;
 #endif
@@ -4678,6 +4688,12 @@ do_reload (void)
   df_scan_alloc (NULL);
   df_scan_blocks ();
 
+  if (optimize > 1)
+    {
+      df_live_add_problem ();
+      df_live_set_all_dirty ();
+    }
+
   if (optimize)
     df_analyze ();