re PR rtl-optimization/88390 (g++.dg/tree-prof/pr57451.C FAILs)

	PR rtl-optimization/88390
	* dwarf2cfi.c (struct dw_cfi_row): Add window_save field.
	(cfi_row_equal_p): Compare it.
	(dwarf2out_frame_debug_cfa_window_save): Add FAKE parameter.
	If FAKE is false, set window_save of the current row.
	(dwarf2out_frame_debug) <REG_CFA_TOGGLE_RA_MANGLE>: Call above
	function with FAKE parameter set to true.
	<REG_CFA_WINDOW_SAVE>: Likewise but with FAKE parameter set to false.
	(change_cfi_row): Emit a DW_CFA_GNU_window_save if necessary.

From-SVN: r266906

gcc/ChangeLog

+2018-12-08  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR rtl-optimization/88390
+	* dwarf2cfi.c (struct dw_cfi_row): Add window_save field.
+	(cfi_row_equal_p): Compare it.
+	(dwarf2out_frame_debug_cfa_window_save): Add FAKE parameter.
+	If FAKE is false, set window_save of the current row.
+	(dwarf2out_frame_debug) <REG_CFA_TOGGLE_RA_MANGLE>: Call above
+	function with FAKE parameter set to true.
+	<REG_CFA_WINDOW_SAVE>: Likewise but with FAKE parameter set to false.
+	(change_cfi_row): Emit a DW_CFA_GNU_window_save if necessary.
+
 2018-12-07  Peter Bergner  <bergner@linux.ibm.com>
 
 	PR target/87496

gcc/dwarf2cfi.c

@@ -68,6 +68,9 @@ struct GTY(()) dw_cfi_row
 
   /* The expressions for any register column that is saved.  */
   cfi_vec reg_save;
+
+  /* True if the register window is saved.  */
+  bool window_save;
 };
 
 /* The caller's ORIG_REG is saved in SAVED_IN_REG.  */
@@ -766,6 +769,9 @@ cfi_row_equal_p (dw_cfi_row *a, dw_cfi_row *b)
         return false;
     }
 
+  if (a->window_save != b->window_save)
+    return false;
+
   return true;
 }
 
@@ -1364,16 +1370,20 @@ dwarf2out_frame_debug_cfa_restore (rtx reg)
 }
 
 /* A subroutine of dwarf2out_frame_debug, process a REG_CFA_WINDOW_SAVE.
-   ??? Perhaps we should note in the CIE where windows are saved (instead of
-   assuming 0(cfa)) and what registers are in the window.  */
+   FAKE is true if this is not really a window save but something else.
+
+   ??? Perhaps we should note in the CIE where windows are saved (instead
+   of assuming 0(cfa)) and what registers are in the window.  */
 
 static void
-dwarf2out_frame_debug_cfa_window_save (void)
+dwarf2out_frame_debug_cfa_window_save (bool fake)
 {
   dw_cfi_ref cfi = new_cfi ();
 
   cfi->dw_cfi_opc = DW_CFA_GNU_window_save;
   add_cfi (cfi);
+  if (!fake)
+    cur_row->window_save = true;
 }
 
 /* Record call frame debugging information for an expression EXPR,
@@ -2133,9 +2143,13 @@ dwarf2out_frame_debug (rtx_insn *insn)
 	break;
 
       case REG_CFA_TOGGLE_RA_MANGLE:
+	/* This uses the same DWARF opcode as the next operation.  */
+	dwarf2out_frame_debug_cfa_window_save (true);
+	handled_one = true;
+	break;
+
       case REG_CFA_WINDOW_SAVE:
-	/* We overload both of these operations onto the same DWARF opcode.  */
-	dwarf2out_frame_debug_cfa_window_save ();
+	dwarf2out_frame_debug_cfa_window_save (false);
 	handled_one = true;
 	break;
 
@@ -2199,6 +2213,14 @@ change_cfi_row (dw_cfi_row *old_row, dw_cfi_row *new_row)
       else if (!cfi_equal_p (r_old, r_new))
         add_cfi (r_new);
     }
+
+  if (!old_row->window_save && new_row->window_save)
+    {
+      dw_cfi_ref cfi = new_cfi ();
+
+      cfi->dw_cfi_opc = DW_CFA_GNU_window_save;
+      add_cfi (cfi);
+    }
 }
 
 /* Examine CFI and return true if a cfi label and set_loc is needed