PING: PATCH to expand_used_vars for debug/42800 (P1 regression)

[Jason Merrill <jason at redhat dot com>]

On 02/19/2010 05:18 PM, Jason Merrill wrote:
> The problem is this PR is that when are writing out the debug info for
> the temporary containing the upper bound of the VLA, its rtl still
> refers to virtual regs, so dwarf2out gives up and doesn't emit any debug
> info for the upper bound. This happens because the Expand from SSA patch
> broke Jakub's patch for PR 34037, such that expand_used_vars is no
> longer re-adding the variable to cfun->local_decls.
>
> The patch adjusts the logic in expand_used_vars so that the PR 34037 fix
> is executed again for this variable.
>
> Tested x86_64-pc-linux-gnu. OK for trunk?

commit 7b71cfa84b5c7e3c169f25e057789b5053a2b640
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Feb 19 14:40:57 2010 -0500

    	PR debug/42800
    	* cfgexpand.c (expand_used_vars): Keep artificial non-ignored vars
    	in cfun->local_decls even if they have register types.

diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 53beecd..ee26ee4 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -1331,8 +1331,7 @@ expand_used_vars (void)
       if (is_gimple_reg (var))
 	{
 	  TREE_USED (var) = 0;
-	  ggc_free (t);
-	  continue;
+	  goto next;
 	}
       /* We didn't set a block for static or extern because it's hard
 	 to tell the difference between a global variable (re)declared
@@ -1353,20 +1352,20 @@ expand_used_vars (void)
       TREE_USED (var) = 1;
 
       if (expand_now)
+	expand_one_var (var, true, true);
+
+    next:
+      if (DECL_ARTIFICIAL (var) && !DECL_IGNORED_P (var))
 	{
-	  expand_one_var (var, true, true);
-	  if (DECL_ARTIFICIAL (var) && !DECL_IGNORED_P (var))
-	    {
-	      rtx rtl = DECL_RTL_IF_SET (var);
+	  rtx rtl = DECL_RTL_IF_SET (var);
 
-	      /* Keep artificial non-ignored vars in cfun->local_decls
-		 chain until instantiate_decls.  */
-	      if (rtl && (MEM_P (rtl) || GET_CODE (rtl) == CONCAT))
-		{
-		  TREE_CHAIN (t) = cfun->local_decls;
-		  cfun->local_decls = t;
-		  continue;
-		}
+	  /* Keep artificial non-ignored vars in cfun->local_decls
+	     chain until instantiate_decls.  */
+	  if (rtl && (MEM_P (rtl) || GET_CODE (rtl) == CONCAT))
+	    {
+	      TREE_CHAIN (t) = cfun->local_decls;
+	      cfun->local_decls = t;
+	      continue;
 	    }
 	}
 
diff --git a/gcc/testsuite/c-c++-common/dwarf2/vla1.c b/gcc/testsuite/c-c++-common/dwarf2/vla1.c
new file mode 100644
index 0000000..e814bf5
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/dwarf2/vla1.c
@@ -0,0 +1,11 @@
+// PR debug/42800
+// { dg-options "-gdwarf-2 -dA" }
+// { dg-final { scan-assembler "DW_AT_upper_bound" } }
+
+int
+f (int i)
+{
+  char a[i];
+
+  return a[0];
+}
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/dwarf2.exp b/gcc/testsuite/g++.dg/debug/dwarf2/dwarf2.exp
index 1255d06..1a874f8 100644
--- a/gcc/testsuite/g++.dg/debug/dwarf2/dwarf2.exp
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/dwarf2.exp
@@ -35,7 +35,7 @@ set comp_output [g++_target_compile \
 if { ! [string match "*: target system does not support the * debug format*" \
     $comp_output] } {
     remove-build-file "trivial.S"
-    dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.\[C\]]] \
+    dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.C $srcdir/c-c++-common/dwarf2/*.c]] \
 	    "" $DEFAULT_CFLAGS
 }
 
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/dwarf2.exp b/gcc/testsuite/gcc.dg/debug/dwarf2/dwarf2.exp
index 73c2c44..74136ae 100644
--- a/gcc/testsuite/gcc.dg/debug/dwarf2/dwarf2.exp
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/dwarf2.exp
@@ -35,7 +35,7 @@ set comp_output [gcc_target_compile \
 if { ! [string match "*: target system does not support the * debug format*" \
     $comp_output] } {
     remove-build-file "trivial.S"
-    dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.\[cS\]]] \
+    dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.\[cS\] $srcdir/c-c++-common/dwarf2/*.c]] \
 	    "" $DEFAULT_CFLAGS
 }