Don't attempt to analyze values which are obviously undef. This fixes some
assertion failures in extreme cases.
llvm-svn: 102042
diff --git a/llvm/test/Analysis/ScalarEvolution/undefined.ll b/llvm/test/Analysis/ScalarEvolution/undefined.ll
new file mode 100644
index 0000000..b1f4446
--- /dev/null
+++ b/llvm/test/Analysis/ScalarEvolution/undefined.ll
@@ -0,0 +1,39 @@
+; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
+
+; ScalarEvolution shouldn't attempt to interpret expressions which have
+; undefined results.
+
+define void @foo(i64 %x) {
+
+ %a = udiv i64 %x, 0
+; CHECK: --> (%x /u 0)
+
+ %B = shl i64 %x, 64
+; CHECK: --> %B
+
+ %b = ashr i64 %B, 64
+; CHECK: --> %b
+
+ %c = lshr i64 %x, 64
+; CHECK: --> %c
+
+ %d = shl i64 %x, 64
+; CHECK: --> %d
+
+ %E = shl i64 %x, -1
+; CHECK: --> %E
+
+ %e = ashr i64 %E, -1
+; CHECK: --> %e
+
+ %f = lshr i64 %x, -1
+; CHECK: --> %f
+
+ %g = shl i64 %x, -1
+; CHECK: --> %g
+
+ %h = bitcast i64 undef to i64
+; CHECK: --> undef
+
+ ret void
+}