36 lines
1.4 KiB
LLVM
36 lines
1.4 KiB
LLVM
; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
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; CHECK: Determining loop execution counts for: @test
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; CHECK: Loop %for.body: backedge-taken count is ((-2 + %len) /u 2)
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; CHECK: Loop %for.body: max backedge-taken count is 1073741823
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define zeroext i16 @test(i16* nocapture %p, i32 %len) nounwind readonly {
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entry:
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%cmp2 = icmp sgt i32 %len, 1
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br i1 %cmp2, label %for.body.preheader, label %for.end
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for.body.preheader: ; preds = %entry
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br label %for.body
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for.body: ; preds = %for.body, %for.body.preheader
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%p.addr.05 = phi i16* [ %incdec.ptr, %for.body ], [ %p, %for.body.preheader ]
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%len.addr.04 = phi i32 [ %sub, %for.body ], [ %len, %for.body.preheader ]
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%res.03 = phi i32 [ %add, %for.body ], [ 0, %for.body.preheader ]
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%incdec.ptr = getelementptr inbounds i16, i16* %p.addr.05, i32 1
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%0 = load i16, i16* %p.addr.05, align 2
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%conv = zext i16 %0 to i32
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%add = add i32 %conv, %res.03
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%sub = add nsw i32 %len.addr.04, -2
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%cmp = icmp sgt i32 %sub, 1
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br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
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for.cond.for.end_crit_edge: ; preds = %for.body
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%extract.t = trunc i32 %add to i16
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br label %for.end
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for.end: ; preds = %for.cond.for.end_crit_edge, %entry
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%res.0.lcssa.off0 = phi i16 [ %extract.t, %for.cond.for.end_crit_edge ], [ 0, %entry ]
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ret i16 %res.0.lcssa.off0
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}
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