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2b0ecb2758
Summary: Teach `isHighCostExpansion` to consider divisions by power-of-two constants as cheap and add a test case. This change is needed for a new user of `isHighCostExpansion` that will be added in a subsequent change. Depends on D8995. Reviewers: atrick Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D8993 llvm-svn: 234845
30 lines
866 B
LLVM
30 lines
866 B
LLVM
; RUN: opt < %s -indvars -S | FileCheck %s
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
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; It is okay to do LFTR on this loop even though the trip count is a
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; division because in this case the division can be optimized to a
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; shift.
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define void @foo(i8* %a, i8 %n) nounwind uwtable ssp {
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; CHECK-LABEL: @foo(
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entry:
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%e = icmp sgt i8 %n, 3
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br i1 %e, label %loop, label %exit
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loop:
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; CHECK-LABEL: loop:
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%i = phi i8 [ 0, %entry ], [ %i.inc, %loop ]
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%i1 = phi i8 [ 0, %entry ], [ %i1.inc, %loop ]
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%i.inc = add nsw i8 %i, 4
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%i1.inc = add i8 %i1, 1
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store volatile i8 0, i8* %a
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%c = icmp slt i8 %i, %n
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; CHECK-LABEL: %exitcond = icmp ne i8 %i1.inc
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br i1 %c, label %loop, label %exit
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exit:
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; CHECK-LABEL: exit:
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ret void
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}
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