Bootstrapped and regtested on x86_64-redhat-linux, s390x-redhat-linux
and ppc64le-redhat-linux. OK for trunk and gcc-9-branch?
try_forward_edges does not update dominance info, and merge_blocks
relies on it being up-to-date. In PR92430 stale dominance info makes
merge_blocks produce a loop in the dominator tree, which in turn makes
delete_basic_block loop forever.
Fix by freeing dominance info at the beginning of cleanup_cfg.
gcc/ChangeLog:
2019-11-12 Ilya Leoshkevich <i...@linux.ibm.com>
PR rtl-optimization/92430
* cfgcleanup.c (pass_jump_after_combine::execute): Free
dominance info at the beginning.
gcc/testsuite/ChangeLog:
2019-11-12 Ilya Leoshkevich <i...@linux.ibm.com>
PR rtl-optimization/92430
* gcc.dg/pr92430.c: New test (from Arseny Solokha).
---
gcc/cfgcleanup.c | 3 +++
gcc/testsuite/gcc.dg/pr92430.c | 25 +++++++++++++++++++++++++
2 files changed, 28 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/pr92430.c
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index 835f7d79ea4..20096de88b4 100644
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -3312,6 +3312,9 @@ public:
unsigned int
pass_jump_after_combine::execute (function *)
{
+ /* Jump threading does not keep dominators up-to-date. */
+ free_dominance_info (CDI_DOMINATORS);
+ free_dominance_info (CDI_POST_DOMINATORS);
cleanup_cfg (flag_thread_jumps ? CLEANUP_THREADING : 0);
return 0;
}
diff --git a/gcc/testsuite/gcc.dg/pr92430.c b/gcc/testsuite/gcc.dg/pr92430.c
new file mode 100644
index 00000000000..915606893ba
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr92430.c
@@ -0,0 +1,25 @@
+// PR rtl-optimization/92430
+// { dg-do compile }
+// { dg-options "-Os -fno-if-conversion -fno-tree-dce -fno-tree-loop-optimize
-fno-tree-vrp" }
+
+int eb, ko;
+
+void
+e9 (int pe, int lx)
+{
+ int ir;
+
+ for (ir = 0; ir < 1; ++ir)
+ {
+ for (ko = 0; ko < 1; ++ko)
+ {
+ for (eb = 0; eb < 1; ++eb)
+ ko += pe;
+
+ for (ko = 0; ko < 1; ++ko)
+ ;
+ }
+
+ pe = ir = lx;
+ }
+}
--
2.23.0
