backport: re PR target/88861 (ICE in calc_dfs_tree, at dominance.c:458)

	Backported from mainline
	2019-01-16  David Malcolm  <dmalcolm@redhat.com>

	PR target/88861
	* combine.c (delete_noop_moves): Convert to "bool" return,
	returning true if any edges are eliminated.
	(combine_instructions): Also return true if delete_noop_moves
	returns true.

	* g++.dg/opt/pr89188.C: Include ../torture/pr88861.C.

	2019-01-16  David Malcolm  <dmalcolm@redhat.com>

	PR target/88861
	* g++.dg/torture/pr88861.C: New test.

From-SVN: r275106

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 993796fb04a2b32e8c349f94867a6dd32638ecb8..99e38ac01621cf7c7ae314915e3fc296825f9030 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,14 @@
 2019-08-30  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline
+       2019-01-16  David Malcolm  <dmalcolm@redhat.com>
+
+       PR target/88861
+       * combine.c (delete_noop_moves): Convert to "bool" return,
+       returning true if any edges are eliminated.
+       (combine_instructions): Also return true if delete_noop_moves
+       returns true.
+
        2019-02-08  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/89234

diff --git a/gcc/combine.c b/gcc/combine.c
index 685b0db62e58d5d0415321a5a7e5acbaeb1867a4..ee4f1e19c45b49ae24952779c0e311b7b504df4e 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -962,14 +962,17 @@ combine_validate_cost (rtx_insn *i0, rtx_insn *i1, rtx_insn *i2, rtx_insn *i3,
 }
 
 
-/* Delete any insns that copy a register to itself.  */
+/* Delete any insns that copy a register to itself.
+   Return true if the CFG was changed.  */
 
-static void
+static bool
 delete_noop_moves (void)
 {
   rtx_insn *insn, *next;
   basic_block bb;
 
+  bool edges_deleted = false;
+
   FOR_EACH_BB_FN (bb, cfun)
     {
       for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); insn = next)
@@ -980,10 +983,12 @@ delete_noop_moves (void)
              if (dump_file)
                fprintf (dump_file, "deleting noop move %d\n", INSN_UID (insn));
 
-             delete_insn_and_edges (insn);
+             edges_deleted |= delete_insn_and_edges (insn);
            }
        }
     }
+
+  return edges_deleted;
 }
 
 \f
@@ -1122,8 +1127,8 @@ insn_a_feeds_b (rtx_insn *a, rtx_insn *b)
 /* Main entry point for combiner.  F is the first insn of the function.
    NREGS is the first unused pseudo-reg number.
 
-   Return nonzero if the combiner has turned an indirect jump
-   instruction into a direct jump.  */
+   Return nonzero if the CFG was changed (e.g. if the combiner has
+   turned an indirect jump instruction into a direct jump).  */
 static int
 combine_instructions (rtx_insn *f, unsigned int nregs)
 {
@@ -1501,7 +1506,7 @@ retry:
   default_rtl_profile ();
   clear_bb_flags ();
   new_direct_jump_p |= purge_all_dead_edges ();
-  delete_noop_moves ();
+  new_direct_jump_p |= delete_noop_moves ();
 
   /* Clean up.  */
   obstack_free (&insn_link_obstack, NULL);

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c416a1d4382c217bf867e496b8194360f9e616ad..ac912ab819b50154184ac4cc6a9622202b33cc15 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,16 @@
 2019-08-30  Jakub Jelinek  <jakub@redhat.com>
 
        Backported from mainline
+       2019-02-09  Jakub Jelinek  <jakub@redhat.com>
+
+       PR target/88861
+       * g++.dg/opt/pr89188.C: Include ../torture/pr88861.C.
+
+       2019-01-16  David Malcolm  <dmalcolm@redhat.com>
+
+       PR target/88861
+       * g++.dg/torture/pr88861.C: New test.
+
        2019-02-08  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/89234

diff --git a/gcc/testsuite/g++.dg/opt/pr89188.C b/gcc/testsuite/g++.dg/opt/pr89188.C
index cb0ea7968db3547a5de39fdaa2910e97f78f7f79..80be23763c7fd469fbefb806fa07193571052e7d 100644 (file)
--- a/gcc/testsuite/g++.dg/opt/pr89188.C
+++ b/gcc/testsuite/g++.dg/opt/pr89188.C
@@ -2,12 +2,4 @@
 // { dg-do compile { target c++11 } }
 // { dg-options "-Og -flive-range-shrinkage -fnon-call-exceptions" }
 
-struct Ax {
-  int n, a[];
-};
-
-int i = 12345678;
-int main() {
-  static Ax s{456, i};
-  ((s.a[0]) ? (void)0 : (void)0);
-}
+#include "../torture/pr88861.C"

diff --git a/gcc/testsuite/g++.dg/torture/pr88861.C b/gcc/testsuite/g++.dg/torture/pr88861.C
new file mode 100644 (file)
index 0000000..d2b6a4b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr88861.C
@@ -0,0 +1,11 @@
+// { dg-options "-fnon-call-exceptions" }
+
+struct Ax {
+  int n, a[];
+};
+
+int i = 12345678;
+int main() {
+  static Ax s{456, i};
+  ((s.a[0]) ? (void)0 : (void)0);
+}