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This is re-land of https://reviews.llvm.org/rL327362 with a fix and regression test. The crash was due to it is possible that for found MDL loop, LHS or RHS may contain an invariant unknown SCEV which does not dominate the MDL. Please see regression test for an example. Reviewers: sanjoy, mkazantsev, reames Reviewed By: mkazantsev Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D44553 llvm-svn: 327822
40 lines
1.2 KiB
LLVM
40 lines
1.2 KiB
LLVM
; RUN: opt < %s -analyze -iv-users -S | FileCheck %s
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; This is a regression test for the commit rL327362.
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:1"
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target triple = "x86_64-unknown-linux-gnu"
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define void @test(i64 %a, i64* %p) {
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entry:
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br label %first_loop
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first_loop:
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%i = phi i64 [20, %entry], [%i.next, %first_loop]
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%i.next = add nuw nsw i64 %i, 1
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%cond1 = icmp ult i64 %i.next, %a
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br i1 %cond1, label %first_loop, label %middle_block
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middle_block:
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%b = load i64, i64* %p
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%cmp = icmp ult i64 %i, %b
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; When SCEV will try to compute the initial value for %j
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; it will observe umax generated by this select.
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; When it will try to simplify this umax it will invoke
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; isKnownPredicate with AddRec for %i and unknown SCEV for %b.
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; As a result we find MDL == first_loop where %b is not available
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; at loop entry.
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; CHECK: IV Users for loop %second_loop with backedge-taken count{{.*}}umax
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%s = select i1 %cmp, i64 %i, i64 %b
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br label %second_loop
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second_loop:
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%j = phi i64 [%s, %middle_block], [%j.next, %second_loop]
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%j.next = add nuw nsw i64 %j, 1
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%cond2 = icmp ult i64 %j.next, 100
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br i1 %cond2, label %second_loop, label %return
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return:
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ret void
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}
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