llvm-project

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; RUN: opt -S -O1 < %s -o %t1.ll
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; RUN: opt -S < %t1.ll -o %t2.ll
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; RUN: opt -S -passes=simplifycfg < %t1.ll -o %t3.ll
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;; Show that there's no difference after running another simplify CFG
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; RUN: diff %t2.ll %t3.ll
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; Test from LoopSink pass, leaves some single-entry single-exit basic blocks.
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; After LoopSink, we get a basic block .exit.loopexit which has one entry and
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; one exit, the only instruction is a branch. Make sure it doesn't show up.
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; Make sure they disappear at -O1.
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@g = global i32 0, align 4
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define i32 @t1(i32, i32) {
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  %3 = icmp eq i32 %1, 0
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  br i1 %3, label %.exit, label %.preheader
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.preheader:
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  %invariant = load i32, ptr @g
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  br label %.b1
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.b1:
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  %iv = phi i32 [ %t7, %.b7 ], [ 0, %.preheader ]
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  %c1 = icmp sgt i32 %iv, %0
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  br i1 %c1, label %.b2, label %.b6
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.b2:
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  %c2 = icmp sgt i32 %iv, 1
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  br i1 %c2, label %.b3, label %.b4
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.b3:
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  %t3 = sub nsw i32 %invariant, %iv
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  br label %.b5
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.b4:
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  %t4 = add nsw i32 %invariant, %iv
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  br label %.b5
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.b5:
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  %p5 = phi i32 [ %t3, %.b3 ], [ %t4, %.b4 ]
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  %t5 = mul nsw i32 %p5, 5
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  br label %.b7
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.b6:
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  %t6 = add nsw i32 %iv, 100
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  br label %.b7
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.b7:
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  %p7 = phi i32 [ %t6, %.b6 ], [ %t5, %.b5 ]
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  %t7 = add nuw nsw i32 %iv, 1
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  %c7 = icmp eq i32 %t7, %p7
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  br i1 %c7, label %.b1, label %.exit
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.exit:
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  ret i32 10
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}
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