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cb24f8cc5c
Summary: We should check if loop size allows us to peel at least one iteration before we do so. Patch by Max Kazantsev! Reviewers: sanjoy, mkuper, efriedma Reviewed By: mkuper Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D30632 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297122 91177308-0d34-0410-b5e6-96231b3b80d8
54 lines
1.2 KiB
LLVM
54 lines
1.2 KiB
LLVM
; RUN: opt < %s -S -loop-unroll -unroll-threshold=4 | FileCheck %s
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define i32 @invariant_backedge_1(i32 %a, i32 %b) {
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; CHECK-LABEL: @invariant_backedge_1
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; CHECK-NOT: %plus = phi
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; CHECK: loop.peel:
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; CHECK: loop:
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; CHECK: %i = phi
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; CHECK: %sum = phi
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entry:
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br label %loop
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loop:
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%i = phi i32 [ 0, %entry ], [ %inc, %loop ]
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%sum = phi i32 [ 0, %entry ], [ %incsum, %loop ]
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%plus = phi i32 [ %a, %entry ], [ %b, %loop ]
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%incsum = add i32 %sum, %plus
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%inc = add i32 %i, 1
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%cmp = icmp slt i32 %i, 1000
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br i1 %cmp, label %loop, label %exit
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exit:
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ret i32 %sum
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}
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; Peeling should fail due to method size.
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define i32 @invariant_backedge_2(i32 %a, i32 %b) {
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; CHECK-LABEL: @invariant_backedge_2
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; CHECK-NOT: loop.peel:
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; CHECK: loop:
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; CHECK: %i = phi
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; CHECK: %sum = phi
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; CHECK: %plus = phi
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entry:
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br label %loop
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loop:
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%i = phi i32 [ 0, %entry ], [ %inc, %loop ]
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%sum = phi i32 [ 0, %entry ], [ %incsum2, %loop ]
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%plus = phi i32 [ %a, %entry ], [ %b, %loop ]
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%incsum = add i32 %sum, %plus
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%incsum2 = add i32 %incsum, %plus
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%inc = add i32 %i, 1
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%cmp = icmp slt i32 %i, 1000
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br i1 %cmp, label %loop, label %exit
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exit:
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ret i32 %sum
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}
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