forked from OSchip/llvm-project
99 lines
4.3 KiB
LLVM
99 lines
4.3 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
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; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>" 2>&1 | FileCheck %s
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; Tests demonstrate the bug reported as PR48225 by Congzhe Cao.
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; When %boolcond = false and %cond = 0:
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; - %cond.false.on.first.iter is false on 1st iteration;
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; - %cond.false.on.second.iter is false on 2nd iteration;
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; - Therefore, their AND is false on first two iterations, and the backedge is taken twice.
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; 'max backedge-taken count is 1' is a bug caused by wrong treatment of AND
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; condition in the computation logic. It should be 2.
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define void @test_and(i1 %boolcond) {
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; CHECK-LABEL: 'test_and'
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; CHECK-NEXT: Classifying expressions for: @test_and
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; CHECK-NEXT: %conv = zext i1 %boolcond to i32
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; CHECK-NEXT: --> (zext i1 %boolcond to i32) U: [0,2) S: [0,2)
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; CHECK-NEXT: %iv = phi i32 [ 0, %entry ], [ %inc, %backedge ]
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; CHECK-NEXT: --> {0,+,1}<nuw><nsw><%loop> U: [0,3) S: [0,3) Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
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; CHECK-NEXT: %or.cond = and i1 %cond.false.on.first.iter, %cond.false.on.second.iter
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; CHECK-NEXT: --> (%cond.false.on.first.iter umin %cond.false.on.second.iter) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
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; CHECK-NEXT: %inc = add nuw nsw i32 %iv, 1
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; CHECK-NEXT: --> {1,+,1}<nuw><nsw><%loop> U: [1,4) S: [1,4) Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
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; CHECK-NEXT: Determining loop execution counts for: @test_and
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; CHECK-NEXT: Loop %loop: <multiple exits> Unpredictable backedge-taken count.
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; CHECK-NEXT: exit count for loop: 2
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; CHECK-NEXT: exit count for backedge: ***COULDNOTCOMPUTE***
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; CHECK-NEXT: Loop %loop: max backedge-taken count is 2
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; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
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;
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entry:
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%conv = zext i1 %boolcond to i32
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br label %loop
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loop:
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%iv = phi i32 [ 0, %entry ], [ %inc, %backedge ]
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%cmp = icmp ult i32 %iv, 2
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br i1 %cmp, label %backedge, label %for.end
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backedge:
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%cond.false.on.first.iter = icmp ne i32 %iv, 0
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%cond.false.on.second.iter = icmp eq i32 %iv, %conv
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%or.cond = and i1 %cond.false.on.first.iter, %cond.false.on.second.iter
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%inc = add nuw nsw i32 %iv, 1
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br i1 %or.cond, label %exit, label %loop
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exit:
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unreachable
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for.end:
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ret void
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}
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; When %boolcond = false and %cond = 0:
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; - %cond.true.on.first.iter is true on 1st iteration;
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; - %cond.true.on.second.iter is true on 2nd iteration;
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; - Therefore, their OR is true on first two iterations, and the backedge is taken twice.
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; 'max backedge-taken count is 1' is a bug caused by wrong treatment of OR
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; condition in the computation logic. It should be 2.
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define void @test_or(i1 %boolcond) {
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; CHECK-LABEL: 'test_or'
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; CHECK-NEXT: Classifying expressions for: @test_or
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; CHECK-NEXT: %conv = zext i1 %boolcond to i32
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; CHECK-NEXT: --> (zext i1 %boolcond to i32) U: [0,2) S: [0,2)
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; CHECK-NEXT: %iv = phi i32 [ 0, %entry ], [ %inc, %backedge ]
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; CHECK-NEXT: --> {0,+,1}<nuw><nsw><%loop> U: [0,3) S: [0,3) Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
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; CHECK-NEXT: %or.cond = or i1 %cond.true.on.first.iter, %cond.true.on.second.iter
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; CHECK-NEXT: --> (%cond.true.on.first.iter umax %cond.true.on.second.iter) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
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; CHECK-NEXT: %inc = add nuw nsw i32 %iv, 1
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; CHECK-NEXT: --> {1,+,1}<nuw><nsw><%loop> U: [1,4) S: [1,4) Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
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; CHECK-NEXT: Determining loop execution counts for: @test_or
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; CHECK-NEXT: Loop %loop: <multiple exits> Unpredictable backedge-taken count.
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; CHECK-NEXT: exit count for loop: 2
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; CHECK-NEXT: exit count for backedge: ***COULDNOTCOMPUTE***
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; CHECK-NEXT: Loop %loop: max backedge-taken count is 2
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; CHECK-NEXT: Loop %loop: Unpredictable predicated backedge-taken count.
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;
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entry:
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%conv = zext i1 %boolcond to i32
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br label %loop
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loop:
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%iv = phi i32 [ 0, %entry ], [ %inc, %backedge ]
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%cmp = icmp ult i32 %iv, 2
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br i1 %cmp, label %backedge, label %for.end
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backedge:
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%cond.true.on.first.iter = icmp eq i32 %iv, 0
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%cond.true.on.second.iter = icmp ne i32 %iv, %conv
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%or.cond = or i1 %cond.true.on.first.iter, %cond.true.on.second.iter
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%inc = add nuw nsw i32 %iv, 1
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br i1 %or.cond, label %loop, label %exit
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exit:
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unreachable
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for.end:
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ret void
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}
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