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Jakub Kuderski ff611e1c1f [Dominators] Visit affected node candidates found at different root levels
Summary:
This patch attempts to fix the DomTree incremental insertion bug found here [[ https://bugs.llvm.org/show_bug.cgi?id=35969 | PR35969 ]] .

When performing an insertion into a piece of unreachable CFG, we may find the same not at different levels. When this happens, the node can turn out to be affected when we find it starting from a node with a lower level in the tree. The level at which we start visitation affects if we consider a node affected or not.

This patch tracks the lowest level at which each node was visited during insertion and allows it to be visited multiple times, if it can cause it to be considered affected.

Reviewers: brzycki, davide, dberlin, grosser

Reviewed By: brzycki

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D42231

llvm-svn: 322993
2018-01-19 21:27:24 +00:00

76 lines
1.1 KiB
LLVM

; RUN: opt < %s -jump-threading -disable-output -verify-dom-info
@global = external global i64, align 8
define void @f() {
bb:
br label %bb1
bb1:
%tmp = load i64, i64* @global, align 8
%tmp2 = icmp eq i64 %tmp, 0
br i1 %tmp2, label %bb27, label %bb3
bb3:
%tmp4 = load i64, i64* @global, align 8
%tmp5 = icmp eq i64 %tmp4, 0
br i1 %tmp5, label %bb6, label %bb7
bb6:
br label %bb7
bb7:
%tmp8 = phi i1 [ true, %bb3 ], [ undef, %bb6 ]
%tmp9 = select i1 %tmp8, i64 %tmp4, i64 0
br i1 false, label %bb10, label %bb23
bb10:
%tmp11 = load i64, i64* @global, align 8
%tmp12 = icmp slt i64 %tmp11, 5
br i1 %tmp12, label %bb13, label %bb17
bb13:
br label %bb14
bb14:
br i1 undef, label %bb15, label %bb16
bb15:
unreachable
bb16:
br label %bb10
bb17:
br label %bb18
bb18:
br i1 undef, label %bb22, label %bb13
bb19:
br i1 undef, label %bb20, label %bb21
bb20:
unreachable
bb21:
br label %bb18
bb22:
br label %bb23
bb23:
br i1 undef, label %bb24, label %bb13
bb24:
br i1 undef, label %bb26, label %bb25
bb25:
br label %bb19
bb26:
br label %bb1
bb27:
br label %bb24
}