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llvm-6502/test/Analysis/ScalarEvolution/infer-via-ranges.ll
Sanjoy Das e027d74733 [SCEV] Make isImpliedCond smarter.
Summary:
This change teaches isImpliedCond to infer things like "X sgt 0" => "X -
1 sgt -1".  The `ConstantRange` class has the logic to do the heavy
lifting, this change simply gets ScalarEvolution to exploit that when
reasonable.

Depends on D8345

Reviewers: atrick

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8346

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232576 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-18 00:41:29 +00:00

31 lines
755 B
LLVM

; RUN: opt -indvars -S < %s | FileCheck %s
define void @infer_via_ranges(i32 *%arr, i32 %n) {
; CHECK-LABEL: @infer_via_ranges
entry:
%first.itr.check = icmp sgt i32 %n, 0
%start = sub i32 %n, 1
br i1 %first.itr.check, label %loop, label %exit
loop:
; CHECK-LABEL: loop:
%idx = phi i32 [ %start, %entry ] , [ %idx.dec, %in.bounds ]
%idx.dec = sub i32 %idx, 1
%abc = icmp sge i32 %idx, 0
; CHECK: br i1 true, label %in.bounds, label %out.of.bounds
br i1 %abc, label %in.bounds, label %out.of.bounds
in.bounds:
; CHECK-LABEL: in.bounds:
%addr = getelementptr i32, i32* %arr, i32 %idx
store i32 0, i32* %addr
%next = icmp sgt i32 %idx.dec, -1
br i1 %next, label %loop, label %exit
out.of.bounds:
ret void
exit:
ret void
}