[Bug debug/90273] [9/10 Regression] GCC runs out of memory building Firefox

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90273

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
I also see

  # DEBUG D#1 => {CLOBBER}
  # DEBUG grayWordD.71258 => D#1

that looks pointless.  Results from removing

grayWord_57(D) ={v} {CLOBBER};

during into-SSA rewrite.  That should instead be

 # DEBUG grayWord => NULL

saving one debug-temp.  Testing

Index: gcc/tree-ssa.c
===================================================================
--- gcc/tree-ssa.c      (revision 270643)
+++ gcc/tree-ssa.c      (working copy)
@@ -358,6 +358,11 @@ insert_debug_temp_for_var_def (gimple_st
       else if (value == error_mark_node)
        value = NULL;
     }
+  else if (gimple_clobber_p (def_stmt))
+    /* We can end up here when rewriting a decl into SSA and coming
+       along a clobber for the original decl.  Turn that into
+       # DEBUG decl => NULL  */
+    value = NULL;
   else if (is_gimple_assign (def_stmt))
     {
       bool no_value = false;