Fix PR2088. Use modulo linear equation solver to compute loop iteration

count.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53810 91177308-0d34-0410-b5e6-96231b3b80d8

test/Analysis/ScalarEvolution/2008-07-19-InfiniteLoop.ll

@@ -0,0 +1,15 @@
+; RUN: llvm-as < %s | opt -analyze -scalar-evolution \
+; RUN:   -scalar-evolution-max-iterations=0 | grep Unpredictable
+; PR2088
+
+define void @fun() {
+entry:
+        br label %loop
+loop:
+        %i = phi i8 [ 0, %entry ], [ %i.next, %loop ]
+        %i.next = add i8 %i, 4
+        %cond = icmp ne i8 %i.next, 6
+        br i1 %cond, label %loop, label %exit
+exit:
+        ret void
+}