Avoid moving pure/const calls that may return twice in tree-ssa-sink:
properly redirecting the associated abnormal edge is non-trivial.
gcc/ChangeLog:
PR tree-optimization/107505
* tree-ssa-sink.cc (statement_sink_location): Additionally
reject ECF_RETURNS_TWICE calls.
gcc/testsuite/ChangeLog:
PR tree-optimization/107505
* gcc.dg/pr107505.c: New test.
---
Preapproved by Richi on the Bugzilla, pushed after testing.
gcc/testsuite/gcc.dg/pr107505.c | 26 ++++++++++++++++++++++++++
gcc/tree-ssa-sink.cc | 5 +++--
2 files changed, 29 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr107505.c
diff --git a/gcc/testsuite/gcc.dg/pr107505.c b/gcc/testsuite/gcc.dg/pr107505.c
new file mode 100644
index 000000000..01270eac9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr107505.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-guess-branch-probability" } */
+
+int n;
+
+void
+bar (void);
+
+__attribute__ ((noinline, returns_twice)) int
+zero (void)
+{
+ return 0;
+}
+
+void
+foo (void)
+{
+ int a = zero ();
+
+ for (n = 0; n < 2; ++n)
+ {
+ }
+
+ if (a)
+ bar ();
+}
diff --git a/gcc/tree-ssa-sink.cc b/gcc/tree-ssa-sink.cc
index 921305201..eb7c2e681 100644
--- a/gcc/tree-ssa-sink.cc
+++ b/gcc/tree-ssa-sink.cc
@@ -263,12 +263,13 @@ statement_sink_location (gimple *stmt, basic_block frombb,
*zero_uses_p = false;
- /* We only can sink assignments and non-looping const/pure calls. */
+ /* We only can sink assignments and const/pure calls that are guaranteed
+ to return exactly once. */
int cf;
if (!is_gimple_assign (stmt)
&& (!is_gimple_call (stmt)
|| !((cf = gimple_call_flags (stmt)) & (ECF_CONST|ECF_PURE))
- || (cf & ECF_LOOPING_CONST_OR_PURE)))
+ || (cf & (ECF_LOOPING_CONST_OR_PURE|ECF_RETURNS_TWICE))))
return false;
/* We only can sink stmts with a single definition. */
--
2.37.2
