re PR target/23774 (dealloc of dynamic stack space breaks backchain)

	PR target/23774
	* config/rs6000/rs6000.md (restore_stack_block): Write the backchain
	word before changing the stack pointer.	 Use gen_frame_mem for MEMs.
	Use UNSPEC_TIE to prevent insn scheduling reordering the insns.
	(restore_stack_nonlocal): Likewise.
	(save_stack_nonlocal): Use template to emit insns, and gen_frame_mem.

From-SVN: r104206

gcc/ChangeLog

+2005-09-13  Alan Modra  <amodra@bigpond.net.au>
+
+	PR target/23774
+	* config/rs6000/rs6000.md (restore_stack_block): Write the backchain
+	word before changing the stack pointer.	 Use gen_frame_mem for MEMs.
+	Use UNSPEC_TIE to prevent insn scheduling reordering the insns.
+	(restore_stack_nonlocal): Likewise.
+	(save_stack_nonlocal): Use template to emit insns, and gen_frame_mem.
+
 2005-09-12  Ian Lance Taylor  <ian@airs.com>
 
 	PR g++/7874

gcc/config/rs6000/rs6000.md

@@ -9347,51 +9347,58 @@
   ""
   "DONE;")
 
+;; Adjust stack pointer (op0) to a new value (op1).
+;; First copy old stack backchain to new location, and ensure that the
+;; scheduler won't reorder the sp assignment before the backchain write.
 (define_expand "restore_stack_block"
-  [(use (match_operand 0 "register_operand" ""))
-   (set (match_dup 2) (match_dup 3))
-   (set (match_dup 0) (match_operand 1 "register_operand" ""))
-   (set (match_dup 3) (match_dup 2))]
+  [(set (match_dup 2) (match_dup 3))
+   (set (match_dup 4) (match_dup 2))
+   (set (match_dup 5) (unspec:BLK [(match_dup 5)] UNSPEC_TIE))
+   (set (match_operand 0 "register_operand" "")
+	(match_operand 1 "register_operand" ""))]
   ""
   "
 {
   operands[2] = gen_reg_rtx (Pmode);
-  operands[3] = gen_rtx_MEM (Pmode, operands[0]);
+  operands[3] = gen_frame_mem (Pmode, operands[0]);
+  operands[4] = gen_frame_mem (Pmode, operands[1]);
+  operands[5] = gen_frame_mem (BLKmode, operands[0]);
 }")
 
 (define_expand "save_stack_nonlocal"
-  [(match_operand 0 "memory_operand" "")
-   (match_operand 1 "register_operand" "")]
+  [(set (match_dup 3) (match_dup 4))
+   (set (match_operand 0 "memory_operand" "") (match_dup 3))
+   (set (match_dup 2) (match_operand 1 "register_operand" ""))]
   ""
   "
 {
-  rtx temp = gen_reg_rtx (Pmode);
   int units_per_word = (TARGET_32BIT) ? 4 : 8;
 
   /* Copy the backchain to the first word, sp to the second.  */
-  emit_move_insn (temp, gen_rtx_MEM (Pmode, operands[1]));
-  emit_move_insn (adjust_address_nv (operands[0], Pmode, 0), temp);
-  emit_move_insn (adjust_address_nv (operands[0], Pmode, units_per_word),
-		  operands[1]);
-  DONE;
+  operands[0] = adjust_address_nv (operands[0], Pmode, 0);
+  operands[2] = adjust_address_nv (operands[0], Pmode, units_per_word);
+  operands[3] = gen_reg_rtx (Pmode);
+  operands[4] = gen_frame_mem (Pmode, operands[1]);
 }")
 
 (define_expand "restore_stack_nonlocal"
-  [(match_operand 0 "register_operand" "")
-   (match_operand 1 "memory_operand" "")]
+  [(set (match_dup 2) (match_operand 1 "memory_operand" ""))
+   (set (match_dup 3) (match_dup 4))
+   (set (match_dup 5) (match_dup 2))
+   (set (match_dup 6) (unspec:BLK [(match_dup 6)] UNSPEC_TIE))
+   (set (match_operand 0 "register_operand" "") (match_dup 3))]
   ""
   "
 {
-  rtx temp = gen_reg_rtx (Pmode);
   int units_per_word = (TARGET_32BIT) ? 4 : 8;
 
   /* Restore the backchain from the first word, sp from the second.  */
-  emit_move_insn (temp,
-		  adjust_address_nv (operands[1], Pmode, 0));
-  emit_move_insn (operands[0],
-		  adjust_address_nv (operands[1], Pmode, units_per_word));
-  emit_move_insn (gen_rtx_MEM (Pmode, operands[0]), temp);
-  DONE;
+  operands[2] = gen_reg_rtx (Pmode);
+  operands[3] = gen_reg_rtx (Pmode);
+  operands[1] = adjust_address_nv (operands[1], Pmode, 0);
+  operands[4] = adjust_address_nv (operands[1], Pmode, units_per_word);
+  operands[5] = gen_frame_mem (Pmode, operands[3]);
+  operands[6] = gen_frame_mem (BLKmode, operands[0]);
 }")
 
 ;; TOC register handling.