[patch] Preserve return statements at -O0

[Eric Botcazou]

Hi,

this patchlet ensures that return statements are preserved at -O0 so that you 
can put a breakpoint on them in the debugger.

Bootstrapped/regtested on x86_64-suse-linux, OK for the mainline?


2011-04-06  Eric Botcazou  <ebotca...@adacore.com>

        * gimple-low.c (lower_gimple_return): When not optimizing, force
        labels associated with user returns to be preserved.


2011-04-06  Eric Botcazou  <ebotca...@adacore.com>

        * gnat.dg/return3.adb: New test.


-- 
Eric Botcazou

Index: gimple-low.c
===================================================================
--- gimple-low.c	(revision 172018)
+++ gimple-low.c	(working copy)
@@ -758,6 +758,9 @@ lower_gimple_return (gimple_stmt_iterato
 
   /* Generate a goto statement and remove the return statement.  */
  found:
+  /* When not optimizing, make sure user returns are preserved.  */
+  if (!optimize && gimple_has_location (stmt))
+    DECL_ARTIFICIAL (tmp_rs.label) = 0;
   t = gimple_build_goto (tmp_rs.label);
   gimple_set_location (t, gimple_location (stmt));
   gimple_set_block (t, gimple_block (stmt));

-- { dg-do compile { target *-*-linux* } }
-- { dg-options "-gdwarf-2 -dA" }

procedure Return3 is
begin
  return;
end;

-- { dg-final { scan-assembler "loc 1 6" } }