The current SSA conversion kinda ignore undefined variables.
Those may then later be detected when they are part of a
LOAD + (ADD|SUB) cycle but they can also create other cycles
which are not detected.
These cycles inhibit (or uselessly complicate) lots of optimizations.
For example, code like:
and.32 %r2 <- %r1, $1
and.32 %r3 <- %r2, $1
should be simplified into:
and.32 %r3 <- %r1, $1
but this simplification would behave horribly with 'cycles' like:
and.32 %r1 <- %r1, $1
This patch add a testcase for a number a very simple situations
where such cycles can be created.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
validation/infinite-loop01.c | 54 ++++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)
create mode 100644 validation/infinite-loop01.c
diff --git a/validation/infinite-loop01.c b/validation/infinite-loop01.c
new file mode 100644
index 000000000..521cfb4d4
--- /dev/null
+++ b/validation/infinite-loop01.c
@@ -0,0 +1,54 @@
+void fnp(void)
+{
+ int a;
+ for (;;)
+ a += 1;
+}
+
+void fnm(void)
+{
+ int a;
+ for (;;)
+ a -= 1;
+}
+
+void fna(void)
+{
+ int a;
+ for (;;)
+ a &= 1;
+}
+
+void fno(void)
+{
+ int a;
+ for (;;)
+ a |= 1;
+}
+
+void fnx(void)
+{
+ int a;
+ for (;;)
+ a ^= 1;
+}
+
+void fnl(void)
+{
+ int a;
+ for (;;)
+ a <<= 1;
+}
+
+void fnr(void)
+{
+ int a;
+ for (;;)
+ a >>= 1;
+}
+
+/*
+ * check-name: infinite loop 01
+ * check-command: sparse -Wno-decl $file
+ * check-timeout:
+ */
--
2.18.0
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