re PR target/55023 (hppa: wrong code generated with tail call optimisation)

	PR target/55023
	PR middle-end/64388
	* dse.c (struct insn_info): Mention frame_read set also
	before reload for tail calls on some targets.
	(scan_insn): Revert 2014-12-22 change.  Set frame_read
	also before reload for tail calls if
	HARD_FRAME_POINTER_IS_ARG_POINTER.  Call add_wild_read
	instead of add_non_frame_wild_read for non-const/memset
	tail calls after reload.

From-SVN: r219361

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f3db7fdfb3c79f9d0c6935933475582c052620f2..53eb2f29a19fb2dbc8cee1f29c826cf2da2d0410 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2015-01-08  Jakub Jelinek  <jakub@redhat.com>
+
+       PR target/55023
+       PR middle-end/64388
+       * dse.c (struct insn_info): Mention frame_read set also
+       before reload for tail calls on some targets.
+       (scan_insn): Revert 2014-12-22 change.  Set frame_read
+       also before reload for tail calls if
+       HARD_FRAME_POINTER_IS_ARG_POINTER.  Call add_wild_read
+       instead of add_non_frame_wild_read for non-const/memset
+       tail calls after reload.
+
 2015-01-08  Jason Merrill  <jason@redhat.com>
 
        * ubsan.c (do_ubsan_in_current_function): New.

diff --git a/gcc/dse.c b/gcc/dse.c
index 04c6083a79e67a47e234be879ea4b5d79018880d..1ca1bda41bdc532f137036c5a4e1cf8cb497bc13 100644 (file)
--- a/gcc/dse.c
+++ b/gcc/dse.c
@@ -371,9 +371,11 @@ struct insn_info
        either stack pointer or hard frame pointer based.  This means
        that we have no other choice than also killing all the frame
        pointer based stores upon encountering a const function call.
-     This field is set after reload for const function calls.  Having
-     this set is less severe than a wild read, it just means that all
-     the frame related stores are killed rather than all the stores.  */
+     This field is set after reload for const function calls and before
+     reload for const tail function calls on targets where arg pointer
+     is the frame pointer.  Having this set is less severe than a wild
+     read, it just means that all the frame related stores are killed
+     rather than all the stores.  */
   bool frame_read;
 
   /* This field is only used for the processing of const functions.
@@ -2483,17 +2485,6 @@ scan_insn (bb_info_t bb_info, rtx_insn *insn)
 
       insn_info->cannot_delete = true;
 
-      /* Arguments for a sibling call that are pushed to memory are passed
-        using the incoming argument pointer of the current function.  These
-        may or may not be frame related depending on the target.  Since
-        argument pointer related stores are not currently tracked, we treat
-        a sibling call as though it does a wild read.  */
-      if (SIBLING_CALL_P (insn))
-       {
-         add_wild_read (bb_info);
-         return;
-       }
-
       /* Const functions cannot do anything bad i.e. read memory,
         however, they can read their parameters which may have
         been pushed onto the stack.
@@ -2527,7 +2518,13 @@ scan_insn (bb_info_t bb_info, rtx_insn *insn)
                     const_call ? "const" : "memset", INSN_UID (insn));
 
          /* See the head comment of the frame_read field.  */
-         if (reload_completed)
+         if (reload_completed
+             /* Tail calls are storing their arguments using
+                arg pointer.  If it is a frame pointer on the target,
+                even before reload we need to kill frame pointer based
+                stores.  */
+             || (SIBLING_CALL_P (insn)
+                 && HARD_FRAME_POINTER_IS_ARG_POINTER))
            insn_info->frame_read = true;
 
          /* Loop over the active stores and remove those which are
@@ -2601,7 +2598,11 @@ scan_insn (bb_info_t bb_info, rtx_insn *insn)
                }
            }
        }
-
+      else if (SIBLING_CALL_P (insn) && reload_completed)
+       /* Arguments for a sibling call that are pushed to memory are passed
+          using the incoming argument pointer of the current function.  After
+          reload that might be (and likely is) frame pointer based.  */
+       add_wild_read (bb_info);
       else
        /* Every other call, including pure functions, may read any memory
            that is not relative to the frame.  */