This backports a fix for the omission of a check of trapping mems
when hoisting them across calls that might not return. This was
originally done as part of a fix to handle const functions that throw
properly.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed to the
GCC 11 branch.
2021-08-17 Richard Biener <rguent...@suse.de>
PR tree-optimization/101373
PR tree-optimization/101868
* tree-ssa-pre.c (prune_clobbered_mems): Also prune trapping
references when the BB may not return.
* gcc.dg/lto/pr101868_0.c: New testcase.
* gcc.dg/lto/pr101868_1.c: Likewise.
* gcc.dg/lto/pr101868_2.c: Likewise.
* gcc.dg/lto/pr101868_3.c: Likewise.
---
gcc/testsuite/gcc.dg/lto/pr101868_0.c | 33 +++++++++++++++++++++++++++
gcc/testsuite/gcc.dg/lto/pr101868_1.c | 23 +++++++++++++++++++
gcc/testsuite/gcc.dg/lto/pr101868_2.c | 11 +++++++++
gcc/testsuite/gcc.dg/lto/pr101868_3.c | 8 +++++++
gcc/tree-ssa-pre.c | 7 ++++++
5 files changed, 82 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/lto/pr101868_0.c
create mode 100644 gcc/testsuite/gcc.dg/lto/pr101868_1.c
create mode 100644 gcc/testsuite/gcc.dg/lto/pr101868_2.c
create mode 100644 gcc/testsuite/gcc.dg/lto/pr101868_3.c
diff --git a/gcc/testsuite/gcc.dg/lto/pr101868_0.c
b/gcc/testsuite/gcc.dg/lto/pr101868_0.c
new file mode 100644
index 00000000000..c84d19b0267
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr101868_0.c
@@ -0,0 +1,33 @@
+/* { dg-lto-do run } */
+/* { dg-lto-options { "-O2 -fno-strict-aliasing -flto" } } */
+
+typedef unsigned long VALUE;
+
+__attribute__ ((cold))
+void rb_check_type(VALUE, int);
+
+static VALUE
+repro(VALUE dummy, VALUE hash)
+{
+ if (hash == 0) {
+ rb_check_type(hash, 1);
+ }
+ else if (*(long *)hash) {
+ rb_check_type(hash, 1);
+ }
+
+
+ return *(long *)hash;
+}
+
+static VALUE (*that)(VALUE dummy, VALUE hash) = repro;
+
+int
+main(int argc, char **argv)
+{
+ argc--;
+ that(0, argc);
+
+ rb_check_type(argc, argc);
+
+}
diff --git a/gcc/testsuite/gcc.dg/lto/pr101868_1.c
b/gcc/testsuite/gcc.dg/lto/pr101868_1.c
new file mode 100644
index 00000000000..146c14abc76
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr101868_1.c
@@ -0,0 +1,23 @@
+typedef unsigned long VALUE;
+
+
+__attribute__ ((noreturn)) void rexc_raise(VALUE mesg);
+
+VALUE rb_donothing(VALUE klass);
+
+static void
+funexpected_type(VALUE x, int xt, int t)
+{
+ rexc_raise(rb_donothing(0));
+}
+
+__attribute__ ((cold))
+void
+rb_check_type(VALUE x, int t)
+{
+ int xt;
+
+ if (x == 0) {
+ funexpected_type(x, xt, t);
+ }
+}
diff --git a/gcc/testsuite/gcc.dg/lto/pr101868_2.c
b/gcc/testsuite/gcc.dg/lto/pr101868_2.c
new file mode 100644
index 00000000000..e6f01b23f45
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr101868_2.c
@@ -0,0 +1,11 @@
+typedef unsigned long VALUE;
+
+static void thing(void) {}
+static void (*ptr)(void) = &thing;
+
+VALUE
+rb_donothing(VALUE klass)
+{
+ ptr();
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/lto/pr101868_3.c
b/gcc/testsuite/gcc.dg/lto/pr101868_3.c
new file mode 100644
index 00000000000..61217625be7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr101868_3.c
@@ -0,0 +1,8 @@
+typedef unsigned long VALUE;
+
+__attribute__((noreturn))
+void
+rexc_raise(VALUE mesg)
+{
+ __builtin_exit(0);
+}
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index 04ec4fbaeec..2aedc31e1d7 100644
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -2070,6 +2070,13 @@ prune_clobbered_mems (bitmap_set_t set, basic_block
block)
&& value_dies_in_block_x (expr, block))))
to_remove = i;
}
+ /* If the REFERENCE may trap make sure the block does not contain
+ a possible exit point.
+ ??? This is overly conservative if we translate AVAIL_OUT
+ as the available expression might be after the exit point. */
+ if (BB_MAY_NOTRETURN (block)
+ && vn_reference_may_trap (ref))
+ to_remove = i;
}
else if (expr->kind == NARY)
{
--
2.31.1
