Use block4 form for large debug expressions.

From: Alexandre Oliva <aoliva@redhat.com>

for  gcc/ChangeLog

	PR debug/53135
	* dwarf2out.c (value_format): Use block4 for dw_val_class_loc
	when needed.
---

 gcc/dwarf2out.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)


diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index c776f68..25f57c0 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -7491,6 +7491,8 @@ value_format (dw_attr_ref a)
 	  return DW_FORM_block1;
 	case 2:
 	  return DW_FORM_block2;
+	case 4:
+	  return DW_FORM_block4;
 	default:
 	  gcc_unreachable ();
 	}