From 15b93db9ca258710e3abb43e2378ef3601e3a697 Mon Sep 17 00:00:00 2001 From: David Malcolm Date: Wed, 16 Jan 2019 20:13:23 +0000 Subject: [PATCH] Fix ICE due to "combine" creating unreachable EH blocks (PR target/88861) 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. 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. From-SVN: r267984 --- gcc/ChangeLog | 8 ++++++++ gcc/combine.c | 17 +++++++++++------ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/g++.dg/torture/pr88861.C | 11 +++++++++++ 4 files changed, 35 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/g++.dg/torture/pr88861.C diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9460ad2bcdc..ec90897cae3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2019-01-16 David Malcolm + + 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. + 2019-01-16 Tamar Christina * config/aarch64/aarch64-builtins.c (aarch64_simd_expand_args): Use diff --git a/gcc/combine.c b/gcc/combine.c index e226c7dd353..c108f657c88 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 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) @@ -1001,10 +1004,12 @@ 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; } @@ -1143,8 +1148,8 @@ 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) { @@ -1529,7 +1534,7 @@ 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 004af237dd3..d662e2a90a2 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2019-01-16 David Malcolm + + PR target/88861 + * g++.dg/torture/pr88861.C: New test. + 2019-01-16 Tamar Christina PR debug/88046 diff --git a/gcc/testsuite/g++.dg/torture/pr88861.C b/gcc/testsuite/g++.dg/torture/pr88861.C new file mode 100644 index 00000000000..d2b6a4b7a47 --- /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); +} -- 2.30.2