xtensa-protos.h (xtensa_copy_incoming_a7): Declare.

        * config/xtensa/xtensa-protos.h (xtensa_copy_incoming_a7): Declare.
        * config/xtensa/xtensa.c (struct machine_function): Add
        incoming_a7_copied flag.
        (xtensa_copy_incoming_a7): Define.
        (xtensa_emit_move_sequence): Use xtensa_copy_incoming_a7.
        * config/xtensa/xtensa.md (movdi, movsf, movdf): Ditto.

From-SVN: r59364

4 files changed, 87 insertions, 57 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e3672f9..ab62b50 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2002-11-21  Bob Wilson  <bob.wilson@acm.org>
+
+	* config/xtensa/xtensa-protos.h (xtensa_copy_incoming_a7): Declare.
+	* config/xtensa/xtensa.c (struct machine_function): Add
+	incoming_a7_copied flag.
+	(xtensa_copy_incoming_a7): Define.
+	(xtensa_emit_move_sequence): Use xtensa_copy_incoming_a7.
+	* config/xtensa/xtensa.md (movdi, movsf, movdf): Ditto.
+
 Thu Nov 21 23:52:04 CET 2002  Jan Hubicka  <jH@suse.cz>
 
 	* i386-protos.h (x86_64_sign_extended_value): Fix prototype.
diff --git a/gcc/config/xtensa/xtensa-protos.h b/gcc/config/xtensa/xtensa-protos.h
index 051c81e..195d71d 100644
--- a/gcc/config/xtensa/xtensa-protos.h
+++ b/gcc/config/xtensa/xtensa-protos.h
@@ -70,6 +70,7 @@ extern int xtensa_expand_conditional_move PARAMS ((rtx *, int));
 extern int xtensa_expand_scc PARAMS ((rtx *));
 extern int xtensa_expand_block_move PARAMS ((rtx *));
 extern int xtensa_emit_move_sequence PARAMS ((rtx *, enum machine_mode));
+extern bool xtensa_copy_incoming_a7 PARAMS ((rtx *, enum machine_mode));
 extern void xtensa_emit_block_move PARAMS ((rtx *, rtx *, int));
 extern void xtensa_expand_nonlocal_goto PARAMS ((rtx *));
 extern void xtensa_emit_loop_end PARAMS ((rtx, rtx *));
diff --git a/gcc/config/xtensa/xtensa.c b/gcc/config/xtensa/xtensa.c
index ae7c994..babb5b0 100644
--- a/gcc/config/xtensa/xtensa.c
+++ b/gcc/config/xtensa/xtensa.c
@@ -90,6 +90,7 @@ const char *xtensa_st_opcodes[(int) MAX_MACHINE_MODE];
 struct machine_function GTY(())
 {
   int accesses_prev_frame;
+  bool incoming_a7_copied;
 };
 
 /* Vector, indexed by hard register number, which contains 1 for a
@@ -1275,45 +1276,8 @@ xtensa_emit_move_sequence (operands, mode)
       if (!xtensa_valid_move (mode, operands))
 	operands[1] = force_reg (mode, operands[1]);
 
-      /* Check if this move is copying an incoming argument in a7.  If
-	 so, emit the move, followed by the special "set_frame_ptr"
-	 unspec_volatile insn, at the very beginning of the function.
-	 This is necessary because the register allocator will ignore
-	 conflicts with a7 and may assign some other pseudo to a7.  If
-	 that pseudo was assigned prior to this move, it would clobber
-	 the incoming argument in a7.  By copying the argument out of
-	 a7 as the very first thing, and then immediately following
-	 that with an unspec_volatile to keep the scheduler away, we
-	 should avoid any problems.  */
-
-      if (a7_overlap_mentioned_p (operands[1]))
-	{
-	  rtx mov;
-	  switch (mode)
-	    {
-	    case SImode:
-	      mov = gen_movsi_internal (operands[0], operands[1]);
-	      break;
-	    case HImode:
-	      mov = gen_movhi_internal (operands[0], operands[1]);
-	      break;
-	    case QImode:
-	      mov = gen_movqi_internal (operands[0], operands[1]);
-	      break;
-	    default:
-	      abort ();
-	    }
-
-	  /* Insert the instructions before any other argument copies.
-	     (The set_frame_ptr insn comes _after_ the move, so push it
-	     out first.)  */
-	  push_topmost_sequence ();
-	  emit_insn_after (gen_set_frame_ptr (), get_insns ());
-	  emit_insn_after (mov, get_insns ());
-	  pop_topmost_sequence ();
-
-	  return 1;
-	}
+      if (xtensa_copy_incoming_a7 (operands, mode))
+	return 1;
     }
 
   /* During reload we don't want to emit (subreg:X (mem:Y)) since that
@@ -1345,6 +1309,74 @@ fixup_subreg_mem (x)
 }
 
 
+/* Check if this move is copying an incoming argument in a7.  If so,
+   emit the move, followed by the special "set_frame_ptr"
+   unspec_volatile insn, at the very beginning of the function.  This
+   is necessary because the register allocator will ignore conflicts
+   with a7 and may assign some other pseudo to a7.  If that pseudo was
+   assigned prior to this move, it would clobber the incoming argument
+   in a7.  By copying the argument out of a7 as the very first thing,
+   and then immediately following that with an unspec_volatile to keep
+   the scheduler away, we should avoid any problems.  */
+
+bool
+xtensa_copy_incoming_a7 (operands, mode)
+     rtx *operands;
+     enum machine_mode mode;
+{
+  if (a7_overlap_mentioned_p (operands[1])
+      && !cfun->machine->incoming_a7_copied)
+    {
+      rtx mov;
+      switch (mode)
+	{
+	case DFmode:
+	  mov = gen_movdf_internal (operands[0], operands[1]);
+	  break;
+	case SFmode:
+	  mov = gen_movsf_internal (operands[0], operands[1]);
+	  break;
+	case DImode:
+	  mov = gen_movdi_internal (operands[0], operands[1]);
+	  break;
+	case SImode:
+	  mov = gen_movsi_internal (operands[0], operands[1]);
+	  break;
+	case HImode:
+	  mov = gen_movhi_internal (operands[0], operands[1]);
+	  break;
+	case QImode:
+	  mov = gen_movqi_internal (operands[0], operands[1]);
+	  break;
+	default:
+	  abort ();
+	}
+
+      /* Insert the instructions before any other argument copies.
+	 (The set_frame_ptr insn comes _after_ the move, so push it
+	 out first.)  */
+      push_topmost_sequence ();
+      emit_insn_after (gen_set_frame_ptr (), get_insns ());
+      emit_insn_after (mov, get_insns ());
+      pop_topmost_sequence ();
+
+      /* Ideally the incoming argument in a7 would only be copied
+	 once, since propagating a7 into the body of a function
+	 will almost certainly lead to errors.  However, there is
+	 at least one harmless case (in GCSE) where the original
+	 copy from a7 is changed to copy into a new pseudo.  Thus,
+	 we use a flag to only do this special treatment for the
+	 first copy of a7.  */
+
+      cfun->machine->incoming_a7_copied = true;
+
+      return 1;
+    }
+
+  return 0;
+}
+
+
 /* Try to expand a block move operation to an RTL block move instruction.
    If not optimizing or if the block size is not a constant or if the
    block is small, the expansion fails and GCC falls back to calling
diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index d4f8c84..5db5c0c 100644
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -929,12 +929,8 @@
 	  && !register_operand (operands[1], DImode))
 	operands[1] = force_reg (DImode, operands[1]);
 
-      if (a7_overlap_mentioned_p (operands[1]))
-	{
-	  emit_insn (gen_movdi_internal (operands[0], operands[1]));
-	  emit_insn (gen_set_frame_ptr ());
-	  DONE;
-	}
+      if (xtensa_copy_incoming_a7 (operands, DImode))
+	DONE;
     }
 }")
 
@@ -1107,12 +1103,8 @@
 	      && constantpool_mem_p (operands[1]))))
 	operands[1] = force_reg (SFmode, operands[1]);
 
-      if (a7_overlap_mentioned_p (operands[1]))
-	{
-	  emit_insn (gen_movsf_internal (operands[0], operands[1]));
-	  emit_insn (gen_set_frame_ptr ());
-	  DONE;
-	}
+      if (xtensa_copy_incoming_a7 (operands, SFmode))
+	DONE;
     }
 }")
 
@@ -1193,12 +1185,8 @@
 	  && !register_operand (operands[1], DFmode))
 	operands[1] = force_reg (DFmode, operands[1]);
 
-      if (a7_overlap_mentioned_p (operands[1]))
-	{
-	  emit_insn (gen_movdf_internal (operands[0], operands[1]));
-	  emit_insn (gen_set_frame_ptr ());
-	  DONE;
-	}
+      if (xtensa_copy_incoming_a7 (operands, DFmode))
+	DONE;
     }
 }")