We must be careful which edge we follow for conditions
of a negative form (index != 2).
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
gcc/ChangeLog:
PR tree-optimization/98182
* gimple-if-to-switch.cc (pass_if_to_switch::execute): Request
chain linkage through false edges only.
gcc/testsuite/ChangeLog:
PR tree-optimization/98182
* gcc.dg/tree-ssa/if-to-switch-10.c: New test.
* gcc.dg/tree-ssa/pr98182.c: New test.
---
gcc/gimple-if-to-switch.cc | 6 +++
.../gcc.dg/tree-ssa/if-to-switch-10.c | 44 +++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr98182.c | 18 ++++++++
3 files changed, 68 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/if-to-switch-10.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr98182.c
diff --git a/gcc/gimple-if-to-switch.cc b/gcc/gimple-if-to-switch.cc
index 8e1043ae7c4..311f6f6ac97 100644
--- a/gcc/gimple-if-to-switch.cc
+++ b/gcc/gimple-if-to-switch.cc
@@ -522,6 +522,12 @@ pass_if_to_switch::execute (function *fun)
if (!info2 || info->m_ranges[0].exp != info2->m_ranges[0].exp)
break;
+ /* It is important that the blocks are linked through FALSE_EDGE.
+ For an expression of index != VALUE, true and false edges
+ are flipped. */
+ if (info2->m_false_edge != e)
+ break;
+
chain->m_entries.safe_push (info2);
bitmap_set_bit (seen_bbs, e->src->index);
info = info2;
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/if-to-switch-10.c
b/gcc/testsuite/gcc.dg/tree-ssa/if-to-switch-10.c
new file mode 100644
index 00000000000..7b8da1c9f3c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/if-to-switch-10.c
@@ -0,0 +1,44 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-iftoswitch-optimized" } */
+
+int global;
+int foo ();
+
+int main(int argc, char **argv)
+{
+ if (argc != 1)
+ {
+ if (argc != 2)
+ {
+ if (argc == 3)
+ {
+ foo ();
+ foo ();
+ }
+ else if (argc == 4)
+ {
+ foo ();
+ }
+ else if (argc == 5)
+ {
+ global = 2;
+ }
+ else
+ global -= 123;
+ }
+ else
+ {
+ global += 1;
+ }
+ }
+ else
+ foo ();
+
+
+ global -= 12;
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump "Canonical GIMPLE case clusters: 1 2 3 4 5"
"iftoswitch" } } */
+/* { dg-final { scan-tree-dump "Condition chain with \[^\n\r]\* BBs transformed into a switch
statement." "iftoswitch" } } */
+
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr98182.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr98182.c
new file mode 100644
index 00000000000..29a547e3788
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr98182.c
@@ -0,0 +1,18 @@
+/* PR tree-optimization/98182 */
+/* { dg-do compile } */
+/* { dg-options "-O1 --param case-values-threshold=1
-fdump-tree-iftoswitch-optimized" } */
+
+int global;
+int foo ();
+
+int main(int argc, char **argv)
+{
+ if (argc != 1)
+ __builtin_abort ();
+ else if (argc != 2)
+ __builtin_abort ();
+ else
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump-not "Condition chain" "iftoswitch" } } */
--
2.29.2
