59560e8589
Even though d38205144f was mostly a correct
fix for the external non-PHI users, it's not a *generally* correct fix,
because the 'placeholder' values in those trivial PHI's we create
shouldn't be *always* 'undef', but the PHI itself for the backedges,
else we end up with wrong value, as the `@pr48450_2` test shows.
But we can't just do that, because we can't check that the PHI
can be it's own incoming value when coming from certain predecessor,
because we don't have a dominator tree.
So until we can address this correctness problem properly,
ensure that we don't perform the transformation
if there are such problematic external uses.
Making dominator tree available there is going to be involved,
since `-simplifycfg` pass currently does not preserve/update domtree...
50 lines
1.9 KiB
LLVM
50 lines
1.9 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop-unroll<peeling;no-runtime>,simplify-cfg,instcombine' -unroll-force-peel-count=3 -verify-dom-info | FileCheck %s
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define void @basic(i32 %K, i32 %N) {
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; CHECK-LABEL: @basic(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label [[OUTER:%.*]]
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; CHECK: outer:
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; CHECK-NEXT: [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_INC:%.*]], [[OUTER_BACKEDGE:%.*]] ]
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; CHECK-NEXT: [[CMP_INNER_PEEL:%.*]] = icmp sgt i32 [[K:%.*]], 1
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; CHECK-NEXT: br i1 [[CMP_INNER_PEEL]], label [[INNER_PEEL2:%.*]], label [[OUTER_BACKEDGE]]
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; CHECK: inner.peel2:
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; CHECK-NEXT: [[CMP_INNER_PEEL8:%.*]] = icmp sgt i32 [[K]], 3
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; CHECK-NEXT: br i1 [[CMP_INNER_PEEL8]], label [[INNER:%.*]], label [[OUTER_BACKEDGE]]
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; CHECK: inner:
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; CHECK-NEXT: [[J:%.*]] = phi i32 [ [[J_INC:%.*]], [[INNER]] ], [ 3, [[INNER_PEEL2]] ]
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; CHECK-NEXT: [[J_INC]] = add nuw nsw i32 [[J]], 1
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; CHECK-NEXT: [[CMP_INNER:%.*]] = icmp slt i32 [[J_INC]], [[K]]
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; CHECK-NEXT: br i1 [[CMP_INNER]], label [[INNER]], label [[OUTER_BACKEDGE]], [[LOOP0:!llvm.loop !.*]]
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; CHECK: outer.backedge:
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; CHECK-NEXT: [[I_INC]] = add i32 [[I]], 1
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; CHECK-NEXT: [[CMP_OUTER:%.*]] = icmp slt i32 [[I_INC]], [[N:%.*]]
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; CHECK-NEXT: br i1 [[CMP_OUTER]], label [[OUTER]], label [[END:%.*]]
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; CHECK: end:
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; CHECK-NEXT: ret void
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;
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entry:
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br label %outer
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outer:
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%i = phi i32 [ 0, %entry ], [ %i.inc, %outer.backedge ]
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br label %inner
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inner:
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%j = phi i32 [ 0, %outer ], [ %j.inc, %inner ]
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%j.inc = add i32 %j, 1
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%cmp.inner = icmp slt i32 %j.inc, %K
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br i1 %cmp.inner, label %inner, label %outer.backedge, !llvm.loop !1
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outer.backedge:
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%i.inc = add i32 %i, 1
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%cmp.outer = icmp slt i32 %i.inc, %N
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br i1 %cmp.outer, label %outer, label %end
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end:
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ret void
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}
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!1 = distinct !{!1}
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