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The commit rL308422 introduces a restriction for folding unconditional branches. Specifically if empty block with unconditional branch leads to header of the loop then elimination of this basic block is prohibited. However it seems this condition is redundantly strict. If elimination of this basic block does not introduce more back edges then we can eliminate this block. The patch implements this relax of restriction. The test profile/Linux/counter_promo_nest.c in compiler-rt project is updated to meet this change. Reviewers: efriedma, mcrosier, pacxx, hsung, davidxl Reviewed By: pacxx Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D42691 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324572 91177308-0d34-0410-b5e6-96231b3b80d8
19 lines
423 B
LLVM
19 lines
423 B
LLVM
; RUN: opt < %s -simplifycfg -S | FileCheck %s
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; Check that we can get rid of empty block leading to header
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; if it does not introduce new edge.
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define i32 @test(i32 %c) {
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entry:
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br label %header
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header:
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%i = phi i32 [0, %entry], [%i.1, %backedge]
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%i.1 = add i32 %i, 1
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%cmp = icmp slt i32 %i.1, %c
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br i1 %cmp, label %backedge, label %exit
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; CHECK-NOT: backedge:
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backedge:
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br label %header
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exit:
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ret i32 %i
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}
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