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dd01838ee9
Summary: This removes some duplicated code, and also helps optimization: e.g. in the test case added, `%idx ULT 128` in `@x` is not currently optimized to `true` by `-indvars` but will be, after this change. The only functional change in ths commit is that for add recurrences, ScalarEvolution::getRange will be more aggressive -- computing the unsigned (resp. signed) range for a SCEVAddRecExpr will now look at the NSW (resp. NUW) bits and check for signed (resp. unsigned) overflow. This can be a strict improvement in some cases (such as the attached test case), and should be no worse in other cases. Reviewers: atrick, nlewycky Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D8142 llvm-svn: 231709
40 lines
882 B
LLVM
40 lines
882 B
LLVM
; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
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define void @x(i1* %cond) {
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; CHECK-LABEL: Classifying expressions for: @x
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entry:
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br label %loop
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loop:
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%idx = phi i8 [ 0, %entry ], [ %idx.inc, %loop ]
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; CHECK: %idx = phi i8 [ 0, %entry ], [ %idx.inc, %loop ]
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; CHECK-NEXT: --> {0,+,1}<nuw><nsw><%loop> U: [0,-128) S: [0,-128)
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%idx.inc = add nsw i8 %idx, 1
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%c = load volatile i1, i1* %cond
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br i1 %c, label %loop, label %exit
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exit:
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ret void
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}
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define void @y(i8* %addr) {
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; CHECK-LABEL: Classifying expressions for: @y
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entry:
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br label %loop
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loop:
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%idx = phi i8 [-5, %entry ], [ %idx.inc, %loop ]
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; CHECK: %idx = phi i8 [ -5, %entry ], [ %idx.inc, %loop ]
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; CHECK-NEXT: --> {-5,+,1}<%loop> U: [-5,6) S: [-5,6)
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%idx.inc = add i8 %idx, 1
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%continue = icmp slt i8 %idx.inc, 6
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br i1 %continue, label %loop, label %exit
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exit:
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ret void
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}
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