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f396cc8730
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48529 91177308-0d34-0410-b5e6-96231b3b80d8
27 lines
933 B
LLVM
27 lines
933 B
LLVM
; edgefailure - This function illustrates how SCCP is not doing it's job. This
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; function should be optimized almost completely away: the loop should be
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; analyzed to detect that the body executes exactly once, and thus the branch
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; can be eliminated and code becomes trivially dead. This is distilled from a
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; real benchmark (mst from Olden benchmark, MakeGraph function). When SCCP is
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; fixed, this should be eliminated by a single SCCP application.
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;
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; RUN: llvm-as < %s | opt -sccp | llvm-dis | not grep loop
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define i32* @test() {
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bb1:
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%A = malloc i32 ; <i32*> [#uses=2]
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br label %bb2
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bb2: ; preds = %bb2, %bb1
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;; Always 0
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%i = phi i32 [ %i2, %bb2 ], [ 0, %bb1 ] ; <i32> [#uses=2]
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;; Always 1
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%i2 = add i32 %i, 1 ; <i32> [#uses=2]
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store i32 %i, i32* %A
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;; Always false
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%loop = icmp sle i32 %i2, 0 ; <i1> [#uses=1]
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br i1 %loop, label %bb2, label %bb3
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bb3: ; preds = %bb2
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ret i32* %A
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}
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