PR target/88861 reports an ICE in "ce2" due to an unreachable
basic block.
The block becomes unreachable in "combine" when delete_noop_moves
deletes an insn with a REG_EH_REGION, deleting the EH edge, the
only edge leading to the basic block.
Normally, rest_of_handle_combine would call cleanup_cfg, deleting
unreachable blocks, if combine_instructions returns true, and
combine_instructions does return true for some cases of edge-removal,
but it doesn't for this case, leading to the ICE.
This patch updates delete_noop_moves so that it returns true if
it deletes any edges, and passes that through to combine_instructions,
so that it too will return true if any edges were deleted, ensuring that
cleanup_cfg will be called by rest_of_handle_combine for this case,
deleting the now-unreachable block, and fixing the ICE.
Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu
and on powerpc64le-unknown-linux-gnu.
OK for trunk?
gcc/ChangeLog:
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.
gcc/testsuite/ChangeLog:
PR target/88861
* g++.dg/torture/pr88861.C: New test.
---
gcc/combine.c | 16 ++++++++++------
gcc/testsuite/g++.dg/torture/pr88861.C | 11 +++++++++++
2 files changed, 21 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/torture/pr88861.C
diff --git a/gcc/combine.c b/gcc/combine.c
index a8c9d15..010795e 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -983,14 +983,17 @@ 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 any edges are eliminated. */
-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)
@@ -1001,10 +1004,11 @@ 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;
}
@@ -1143,8 +1147,8 @@ 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 any edges have been removed (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)
{
@@ -1529,7 +1533,7 @@ 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/g++.dg/torture/pr88861.C
b/gcc/testsuite/g++.dg/torture/pr88861.C
new file mode 100644
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);
+}
--
1.8.5.3
