1 files changed, 33 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr22236.c b/gcc/testsuite/gcc.dg/tree-ssa/pr22236.c
new file mode 100644
index 000000000..1986c2f0c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr22236.c
@@ -0,0 +1,33 @@
+/* { dg-do run } */
+/* { dg-options "-O1 -fno-tree-vrp -fwrapv" } */
+
+/* PR tree-optimization/22236
+
+    Avoid conversion of (signed char) {(uchar)1, +, (uchar)1}_x when
+    it is not possible to prove that the scev does not wrap.  
+
+    In this PR, a sequence 1, 2, ..., 255 has to be converted to
+    signed char, but this would wrap: 1, 2, ..., 127, -128, ...  The
+    result should not be a linear scev {(schar)1, +, (schar)1}_x.
+    The conversion should be kept: (schar) {(uchar)1, +, (uchar)1}_x.
+ */
+
+void abort(void);
+
+static inline void
+foo (signed char a)
+{
+  int b = a - 0x7F;
+  if (b > 1)
+    abort();
+}
+
+int main()
+{
+  unsigned char b;
+  for(b = 0; b < 0xFF; b++)
+    foo (b);
+
+  return 0;
+}
+