[PATCH] gimple-fold: Fix ICE in maybe_canonicalize_mem_ref_addr on debug stmt [PR96354]

[Jakub Jelinek via Gcc-patches]

Hi!

In debug stmts, we are less strict about what is and what is not accepted
there, so this patch just punts on optimization of a debug stmt rather than
ICEing.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2020-08-04  Jakub Jelinek  <ja...@redhat.com>

        PR debug/96354
        * gimple-fold.c (maybe_canonicalize_mem_ref_addr): Add IS_DEBUG
        argument.  Return false instead of gcc_unreachable if it is true and
        get_addr_base_and_unit_offset returns NULL.
        (fold_stmt_1) <case GIMPLE_DEBUG>: Adjust caller.

        * g++.dg/opt/pr96354.C: New test.

--- gcc/gimple-fold.c.jj        2020-07-28 15:39:09.908757602 +0200
+++ gcc/gimple-fold.c   2020-08-03 13:23:57.579436442 +0200
@@ -4875,7 +4875,7 @@ replace_stmt_with_simplification (gimple
 /* Canonicalize MEM_REFs invariant address operand after propagation.  */
 
 static bool
-maybe_canonicalize_mem_ref_addr (tree *t)
+maybe_canonicalize_mem_ref_addr (tree *t, bool is_debug = false)
 {
   bool res = false;
   tree *orig_t = t;
@@ -4939,7 +4939,11 @@ maybe_canonicalize_mem_ref_addr (tree *t
          base = get_addr_base_and_unit_offset (TREE_OPERAND (addr, 0),
                                                &coffset);
          if (!base)
-           gcc_unreachable ();
+           {
+             if (is_debug)
+               return false;
+             gcc_unreachable ();
+           }
 
          TREE_OPERAND (*t, 0) = build_fold_addr_expr (base);
          TREE_OPERAND (*t, 1) = int_const_binop (PLUS_EXPR,
@@ -5119,7 +5123,7 @@ fold_stmt_1 (gimple_stmt_iterator *gsi,
          if (*val
              && (REFERENCE_CLASS_P (*val)
                  || TREE_CODE (*val) == ADDR_EXPR)
-             && maybe_canonicalize_mem_ref_addr (val))
+             && maybe_canonicalize_mem_ref_addr (val, true))
            changed = true;
        }
       break;
--- gcc/testsuite/g++.dg/opt/pr96354.C.jj       2020-07-29 11:25:15.701164242 
+0200
+++ gcc/testsuite/g++.dg/opt/pr96354.C  2020-07-29 11:26:16.490291018 +0200
@@ -0,0 +1,24 @@
+// PR debug/96354
+// { dg-do compile }
+// { dg-options "-O2 -g -fopenmp-simd" }
+
+template <int N> struct A { typedef double T[N]; };
+template <int N> struct B { typename A<N>::T b; double *baz () { return b; } };
+template <int N> struct C { B<N> d; C (); };
+template <int N> C<N>::C () { double c = *d.baz (); }
+template <int N> void operator- (C<N>, const C<N> &);
+template <int> struct D {};
+template <int N, int M> C<N> foo (D<N>, C<M>) { C<N> t; return t; }
+int e;
+struct E { D<3> d; void bar (); };
+
+void
+E::bar ()
+{
+#pragma omp simd
+  for (int i = 0; i < e; i++)
+    {
+      C<3> f, g;
+      g - foo (d, f);
+    }
+}

        Jakub