New testcase which caused a bunch of tests to break last night with more

aggressive LICM


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10372 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/LoopSimplify/2003-12-10-ExitBlocksProblem.ll

@@ -0,0 +1,42 @@
+; LoopSimplify is breaking LICM on this testcase because the exit blocks from
+; the loop are reachable from more than just the exit nodes: the exit blocks
+; have predecessors from outside of the loop!
+;
+; This is distilled from a monsterous crafty example.
+
+; RUN: llvm-as < %s | opt -licm | lli
+
+%G = weak global int 0		; <int*> [#uses=13]
+
+implementation   ; Functions:
+
+int %main() {
+entry:
+	store int 123, int* %G
+	br label %loopentry.i
+
+loopentry.i:		; preds = %entry, %endif.1.i
+	%tmp.0.i = load int* %G		; <int> [#uses=1]
+	%tmp.1.i = seteq int %tmp.0.i, 123		; <bool> [#uses=1]
+	br bool %tmp.1.i, label %Out.i, label %endif.0.i
+
+endif.0.i:		; preds = %loopentry.i
+	%tmp.3.i = load int* %G		; <int> [#uses=1]
+	%tmp.4.i = seteq int %tmp.3.i, 126		; <bool> [#uses=1]
+	br bool %tmp.4.i, label %ExitBlock.i, label %endif.1.i
+
+endif.1.i:		; preds = %endif.0.i
+	%tmp.6.i = load int* %G		; <int> [#uses=1]
+	%inc.i = add int %tmp.6.i, 1		; <int> [#uses=1]
+	store int %inc.i, int* %G
+	br label %loopentry.i
+
+Out.i:		; preds = %loopentry.i
+	store int 0, int* %G
+	br label %ExitBlock.i
+
+ExitBlock.i:		; preds = %endif.0.i, %Out.i
+	%tmp.7.i = load int* %G		; <int> [#uses=1]
+	ret int %tmp.7.i
+}
+