From b4fddbe9592e9feb37ce567d90af822b75995531 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Mon, 12 Dec 2022 17:52:46 +0100
Subject: [PATCH] tree-optimization/108076 - if-conversion and forced labels
When doing if-conversion we simply throw away labels without checking
whether they are possibly targets of non-local gotos or have their
address taken. The following rectifies this and refuses to if-convert
such loops.
PR tree-optimization/108076
* tree-if-conv.cc (if_convertible_loop_p_1): Reject blocks
with non-local or forced labels that we later remove
labels from.
* gcc.dg/torture/pr108076.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr108076.c | 17 +++++++++++++++++
gcc/tree-if-conv.cc | 14 ++++++++++++--
2 files changed, 29 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr108076.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr108076.c b/gcc/testsuite/gcc.dg/torture/pr108076.c
new file mode 100644
index 000000000000..ebe2e51bee05
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr108076.c
@@ -0,0 +1,17 @@
+/* { dg-do link } */
+
+static void *j;
+int v, g;
+__attribute__((__leaf__)) int atoi (const char *);
+
+int
+main ()
+{
+ j = &&lab1;
+ &&lab2;
+ atoi ("42");
+lab1:
+lab2:
+ if (v)
+ goto *j;
+}
diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc
index 64b20b4a9e11..0807201cefbd 100644
--- a/gcc/tree-if-conv.cc
+++ b/gcc/tree-if-conv.cc
@@ -1433,10 +1433,20 @@ if_convertible_loop_p_1 (class loop *loop, vec<data_reference_p> *refs)
basic_block bb = ifc_bbs[i];
gimple_stmt_iterator gsi;
+ bool may_have_nonlocal_labels
+ = bb_with_exit_edge_p (loop, bb) || bb == loop->latch;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
switch (gimple_code (gsi_stmt (gsi)))
{
case GIMPLE_LABEL:
+ if (!may_have_nonlocal_labels)
+ {
+ tree label
+ = gimple_label_label (as_a <glabel *> (gsi_stmt (gsi)));
+ if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
+ return false;
+ }
+ /* Fallthru. */
case GIMPLE_ASSIGN:
case GIMPLE_CALL:
case GIMPLE_DEBUG:
@@ -2627,8 +2637,8 @@ remove_conditions_and_labels (loop_p loop)
basic_block bb = ifc_bbs[i];
if (bb_with_exit_edge_p (loop, bb)
- || bb == loop->latch)
- continue;
+ || bb == loop->latch)
+ continue;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
switch (gimple_code (gsi_stmt (gsi)))
--
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