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Subject: [Bug tree-optimization/55920] [4.8 Regression] ICE in expand_debug_locations, at cfgexpand.c:3753
Date: Fri, 11 Jan 2013 16:53:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55920

Martin Jambor <jamborm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jamborm at gcc dot gnu.org

--- Comment #3 from Martin Jambor <jamborm at gcc dot gnu.org> 2013-01-11 16:53:08 UTC ---
As far as the ICE is concerned, I think that if we want to fix it by
reverting patches, we need to revert both the patch for PR 55579 and
PR 54971 (which introduced the generation of the debug statement in
question).

Alternatively, we can punt and put NULL on the right side of the debug
statement when types do not match.  I looked at all places where SRA
generates them and only in sra_modify_assign we can have this problem.
Yes, in 4.9 we can even create a well-typed MEM_REF.  Meanwhile, the
minimal patch (that I am about to bootstrap and test) would be:


2013-01-11  Martin Jambor  <mjambor@suse.cz>

    PR tree-optimization/55920
    * tree-sra.c (sra_modify_assign): Put NULL RHS into debug statement if
    it would have incompatible types.

Index: src/gcc/tree-sra.c
===================================================================
--- src.orig/gcc/tree-sra.c
+++ src/gcc/tree-sra.c
@@ -3108,8 +3108,15 @@ sra_modify_assign (gimple *stmt, gimple_

   if (lacc && lacc->grp_to_be_debug_replaced)
     {
-      gimple ds = gimple_build_debug_bind (get_access_replacement (lacc),
-                       unshare_expr (rhs), *stmt);
+      tree dbg_rhs;
+      gimple ds;
+
+      if (useless_type_conversion_p (lacc->type, TREE_TYPE (rhs)))
+    dbg_rhs = unshare_expr (rhs);
+      else
+    dbg_rhs = NULL_TREE;
+      ds = gimple_build_debug_bind (get_access_replacement (lacc), dbg_rhs,
+                    *stmt);
       gsi_insert_before (gsi, ds, GSI_SAME_STMT);
     }