[PATCH] Fix dwarf2out ICE (PR debug/63342)

[Jakub Jelinek]

Hi!

Since r214899 we ICE on the following testcase, because when
mem_loc_descriptor gives up on a complex TLS related address that
can't be (easily) delegitimized, we try to build location description
from MEM_EXPR, but in this case it is a TARGET_MEM_REF which wasn't handled.
I've implemented more complex handling of TARGET_MEM_REF (attached to the
PR), but we really can't handle SSA_NAMEs anyway, and I doubt there will
be any usable TARGET_MEM_REFs without SSA_NAMEs in them.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok except for the MEM_REF change for 4.9/4.8 (where the mem_loc_descriptor
fix also went)?

2014-10-01  Jakub Jelinek  <ja...@redhat.com>

        PR debug/63342
        * dwarf2out.c (loc_list_from_tree): Handle MEM_REF with non-zero
        offset, TARGET_MEM_REF and SSA_NAME.

        * gcc.dg/pr63342.c: New test.

--- gcc/dwarf2out.c.jj  2014-09-25 10:10:26.000000000 +0200
+++ gcc/dwarf2out.c     2014-09-29 16:39:03.847184205 +0200
@@ -14416,15 +14416,21 @@ loc_list_from_tree (tree loc, int want_a
       break;
 
     case MEM_REF:
-      /* ??? FIXME.  */
       if (!integer_zerop (TREE_OPERAND (loc, 1)))
-       return 0;
+       {
+         have_address = 1;
+         goto do_plus;
+       }
       /* Fallthru.  */
     case INDIRECT_REF:
       list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 0);
       have_address = 1;
       break;
 
+    case TARGET_MEM_REF:
+    case SSA_NAME:
+      return NULL;
+
     case COMPOUND_EXPR:
       return loc_list_from_tree (TREE_OPERAND (loc, 1), want_address);
 
@@ -14587,6 +14593,7 @@ loc_list_from_tree (tree loc, int want_a
 
     case POINTER_PLUS_EXPR:
     case PLUS_EXPR:
+    do_plus:
       if (tree_fits_shwi_p (TREE_OPERAND (loc, 1)))
        {
          list_ret = loc_list_from_tree (TREE_OPERAND (loc, 0), 0);
--- gcc/testsuite/gcc.dg/pr63342.c.jj   2014-09-29 17:02:09.217540570 +0200
+++ gcc/testsuite/gcc.dg/pr63342.c      2014-09-29 17:04:31.797832252 +0200
@@ -0,0 +1,26 @@
+/* PR debug/63342 */
+/* { dg-do compile } */
+/* { dg-options "-g -O2" } */
+/* { dg-additional-options "-fpic" { target fpic } } */
+
+static __thread double u[9], v[9];
+
+void
+foo (double **p, double **q)
+{
+  *p = u;
+  *q = v;
+}
+
+double
+bar (double x)
+{
+  int i;
+  double s = 0.0;
+  for (i = 0; i < 9; i++)
+    {
+      double a = x + v[i];
+      s += u[i] * a * a;
+    }
+  return s;
+}

        Jakub