Check loop exit predicate properly while eliminating one iteration loop.
This patch fixes PR 2869
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57369 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Transforms/LoopIndexSplit/2008-10-10-OneIteration.ll b/test/Transforms/LoopIndexSplit/2008-10-10-OneIteration.ll
new file mode 100644
index 0000000..7c0d207
--- /dev/null
+++ b/test/Transforms/LoopIndexSplit/2008-10-10-OneIteration.ll
@@ -0,0 +1,66 @@
+; RUN: llvm-as < %s | opt -loop-index-split | llvm-dis | grep sle | count 1
+; PR 2869
+
+@w = external global [2 x [2 x i32]] ; <[2 x [2 x i32]]*> [#uses=5]
+
+declare i32 @f() nounwind
+
+define i32 @main() noreturn nounwind {
+entry:
+ br label %bb1.i.outer
+
+bb1.i.outer: ; preds = %bb5.i, %entry
+ %i.0.reg2mem.0.ph.i.ph = phi i32 [ 0, %entry ], [ %4, %bb5.i ] ; <i32> [#uses=3]
+ br label %bb1.i
+
+bb1.i: ; preds = %bb3.i, %bb1.i.outer
+ %j.0.reg2mem.0.i = phi i32 [ %2, %bb3.i ], [ 0, %bb1.i.outer ] ; <i32> [#uses=3]
+ %0 = icmp eq i32 %i.0.reg2mem.0.ph.i.ph, %j.0.reg2mem.0.i ; <i1> [#uses=1]
+ br i1 %0, label %bb2.i, label %bb3.i
+
+bb2.i: ; preds = %bb1.i
+ %1 = getelementptr [2 x [2 x i32]]* @w, i32 0, i32 %i.0.reg2mem.0.ph.i.ph, i32 %j.0.reg2mem.0.i ; <i32*> [#uses=1]
+ store i32 1, i32* %1, align 4
+ br label %bb3.i
+
+bb3.i: ; preds = %bb2.i, %bb1.i
+ %2 = add i32 %j.0.reg2mem.0.i, 1 ; <i32> [#uses=2]
+ %3 = icmp sgt i32 %2, 1 ; <i1> [#uses=1]
+ br i1 %3, label %bb5.i, label %bb1.i
+
+bb5.i: ; preds = %bb3.i
+ %4 = add i32 %i.0.reg2mem.0.ph.i.ph, 1 ; <i32> [#uses=2]
+ %5 = icmp sgt i32 %4, 1 ; <i1> [#uses=1]
+ br i1 %5, label %f.exit, label %bb1.i.outer
+
+f.exit: ; preds = %bb5.i
+ %6 = load i32* getelementptr ([2 x [2 x i32]]* @w, i32 0, i32 0, i32 0), align 4 ; <i32> [#uses=1]
+ %7 = icmp eq i32 %6, 1 ; <i1> [#uses=1]
+ br i1 %7, label %bb, label %bb3
+
+bb: ; preds = %f.exit
+ %8 = load i32* getelementptr ([2 x [2 x i32]]* @w, i32 0, i32 1, i32 1), align 4 ; <i32> [#uses=1]
+ %9 = icmp eq i32 %8, 1 ; <i1> [#uses=1]
+ br i1 %9, label %bb1, label %bb3
+
+bb1: ; preds = %bb
+ %10 = load i32* getelementptr ([2 x [2 x i32]]* @w, i32 0, i32 1, i32 0), align 4 ; <i32> [#uses=1]
+ %11 = icmp eq i32 %10, 0 ; <i1> [#uses=1]
+ br i1 %11, label %bb2, label %bb3
+
+bb2: ; preds = %bb1
+ %12 = load i32* getelementptr ([2 x [2 x i32]]* @w, i32 0, i32 0, i32 1), align 4 ; <i32> [#uses=1]
+ %13 = icmp eq i32 %12, 0 ; <i1> [#uses=1]
+ br i1 %13, label %bb4, label %bb3
+
+bb3: ; preds = %bb2, %bb1, %bb, %f.exit
+ tail call void @abort() noreturn nounwind
+ unreachable
+
+bb4: ; preds = %bb2
+ ret i32 0
+}
+
+declare void @abort() noreturn nounwind
+
+declare void @exit(i32) noreturn nounwind