From 1dd033b8bcb0c50ad80084a3a13a391808b2deb6 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Tue, 21 Feb 2023 13:02:31 +0100
Subject: [PATCH] tree-optimization/108691 - remove trigger-happy assert
The following gets rid of the idea that we should prevent setjmp
like calls from popping up in uncontrolled way in the IL for now.
The solution is probably to handle it similar as noreturn has
the ctrl-altering flag on stmts, but use another flag, for example
ctrl-receiving which would also make sure the stmt is first.
PR tree-optimization/108691
* tree-ssa-dce.cc (eliminate_unnecessary_stmts): Remove
assert about calls_setjmp not becoming true when it was false.
* gcc.dg/pr108691.c: New testcase.
---
gcc/testsuite/gcc.dg/pr108691.c | 9 +++++++++
gcc/tree-ssa-dce.cc | 8 +++++---
2 files changed, 14 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr108691.c
diff --git a/gcc/testsuite/gcc.dg/pr108691.c b/gcc/testsuite/gcc.dg/pr108691.c
new file mode 100644
index 000000000000..e412df10f22c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr108691.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern int __attribute__((returns_twice)) setjmp(void*);
+
+void bbb(void) {
+ int (*fnptr)(void*) = setjmp;
+ fnptr(0);
+}
diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
index ceeb0ad5ab33..0ae998f86f98 100644
--- a/gcc/tree-ssa-dce.cc
+++ b/gcc/tree-ssa-dce.cc
@@ -1512,10 +1512,12 @@ eliminate_unnecessary_stmts (bool aggressive)
remove_edge (to_remove_edges[i]);
cfg_altered = true;
}
- /* When we cleared calls_setjmp we can purge all abnormal edges. Do so. */
- if (cfun->calls_setjmp != had_setjmp)
+ /* When we cleared calls_setjmp we can purge all abnormal edges. Do so.
+ ??? We'd like to assert that setjmp calls do not pop out of nothing
+ but we currently lack a per-stmt way of noting whether a call was
+ recognized as returns-twice (or rather receives-control). */
+ if (!cfun->calls_setjmp && had_setjmp)
{
- gcc_assert (!cfun->calls_setjmp);
/* Make sure we only remove the edges, not dominated blocks. Using
gimple_purge_dead_abnormal_call_edges would do that and we
cannot free dominators yet. */
--
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