[SelectionDAG] Fix for PR30775: Assertion `NodeToMatch->getOpcode() != ISD::DELETED_NODE && "NodeToMatch was removed partway through selection"' failed.

[ABataev]

Summary

NodeToMatch can be modified during matching, but the code does not handle this situation.
Also fixes PR31536

[RKSimon]

Can the test case be reduced any further?

test/CodeGen/X86/dag-update-nodetomatch.ll

14

Add a comment explaining what the test is testing.

[ABataev]

In D29292#661039, @RKSimon wrote:

Can the test case be reduced any further?

It is already reduced. I tried to reduce the reproducer, this is the best I could do.

test/CodeGen/X86/dag-update-nodetomatch.ll

14

Ok, will do

[RKSimon]

Please can you check if this fixes PR31536 as well?

[ABataev]

In D29292#661549, @RKSimon wrote:

Please can you check if this fixes PR31536 as well?

Yes, fixes

[RKSimon]

In D29292#661687, @ABataev wrote:

In D29292#661549, @RKSimon wrote:

Please can you check if this fixes PR31536 as well?

Yes, fixes

Is it worth adding that test case as well?

[ABataev]

In D29292#661693, @RKSimon wrote:

In D29292#661687, @ABataev wrote:

In D29292#661549, @RKSimon wrote:

Please can you check if this fixes PR31536 as well?

Yes, fixes

Is it worth adding that test case as well?

Ok, will add

[ABataev]

Added test from PR31536 + simplified checks + some small changes.

[RKSimon]

Pity the test cases don't reduce any further...

test/CodeGen/X86/dag-update-nodetomatch.ll

14

Please can you add the bugzilla PR number to the comments for each test?

[ABataev]

test/CodeGen/X86/dag-update-nodetomatch.ll

14

Ok, will do

[ABataev]

Added comments with PR numbers to the test

[ABataev]

Other comments?

[RKSimon]

If the test cases won't reduce any further then I guess this is acceptable.

lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

 };
 
 /// \\brief A DAG update listener to keep the matching state
 /// (i.e. RecordedNodes and MatchScope) uptodate if the target is allowed to
 /// change the DAG while matching.  X86 addressing mode matcher is an example
 /// for this.
 class MatchStateUpdater : public SelectionDAG::DAGUpdateListener
 {
-      SmallVectorImpl<std::pair<SDValue, SDNode*> > &RecordedNodes;
-      SmallVectorImpl<MatchScope> &MatchScopes;
+  SDNode **NodeToMatch;
+  SmallVectorImpl<std::pair<SDValue, SDNode *>> &RecordedNodes;
 public:
-  MatchStateUpdater(SelectionDAG &DAG,
-                    SmallVectorImpl<std::pair<SDValue, SDNode*> > &RN,
-                    SmallVectorImpl<MatchScope> &MS) :
-    SelectionDAG::DAGUpdateListener(DAG),
-    RecordedNodes(RN), MatchScopes(MS) { }
+  MatchStateUpdater(SelectionDAG &DAG, SDNode **NodeToMatch,
+                    SmallVectorImpl<std::pair<SDValue, SDNode *>> &RN,
+                    SmallVectorImpl<MatchScope> &MS)
+      : SelectionDAG::DAGUpdateListener(DAG), NodeToMatch(NodeToMatch),
+        RecordedNodes(RN), MatchScopes(MS) {}
 
   void NodeDeleted(SDNode *N, SDNode *E) override {
     // Some early-returns here to avoid the search if we deleted the node or
     // if the update comes from MorphNodeTo (MorphNodeTo is the last thing we
     // do, so it's unnecessary to update matching state at that point).
     // Neither of these can occur currently because we only install this
     // update listener during matching a complex patterns.
     if (!E || E->isMachineOpcode())
       return;
+    // Check if NodeToMatch was updated.
+    if (N == *NodeToMatch)
+      *NodeToMatch = E;
     // Performing linear search here does not matter because we almost never
     // run this code.  You'd have to have a CSE during complex pattern
     // matching.
     for (auto &I : RecordedNodes)
       if (I.first.getNode() == N)
         I.first.setNode(E);
 
     for (auto &I : MatchScopes)
case OPC_CheckComplexPat: {
       unsigned CPNum = MatcherTable[MatcherIndex++];
       unsigned RecNo = MatcherTable[MatcherIndex++];
       assert(RecNo < RecordedNodes.size() && "Invalid CheckComplexPat");
 
       // If target can modify DAG during matching, keep the matching state
       // consistent.
       std::unique_ptr<MatchStateUpdater> MSU;
       if (ComplexPatternFuncMutatesDAG())
-        MSU.reset(new MatchStateUpdater(*CurDAG, RecordedNodes,
+        MSU.reset(new MatchStateUpdater(*CurDAG, &NodeToMatch, RecordedNodes,
                                         MatchScopes));
 
       if (!CheckComplexPattern(NodeToMatch, RecordedNodes[RecNo].second,
                                RecordedNodes[RecNo].first, CPNum,
                                RecordedNodes))
         break;
       continue;
     }

test/CodeGen/X86/dag-update-nodetomatch.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+
+%struct.i = type { i32, i24 }
+%struct.m = type { %struct.i }
+
+@a = local_unnamed_addr global i32 0, align 4
+@b = local_unnamed_addr global i16 0, align 2
+@c = local_unnamed_addr global i16 0, align 2
+@e = local_unnamed_addr global i16 0, align 2
+@l = local_unnamed_addr global %struct.i zeroinitializer, align 4
+@k = local_unnamed_addr global %struct.m zeroinitializer, align 4
+
+@x0 = local_unnamed_addr global double 0.000000e+00, align 8
+@x1 = local_unnamed_addr global i32 0, align 4
+@x2 = local_unnamed_addr global i32 0, align 4
+@x3 = local_unnamed_addr global i32 0, align 4
+@x4 = local_unnamed_addr global i32 0, align 4
+@x5 = local_unnamed_addr global double* null, align 8
+
+; Check that compiler does not crash.
+; Test for PR30775
+define void @_Z1nv() local_unnamed_addr {
+; CHECK-LABEL: _Z1nv:
+entry:
+  %bf.load = load i32, i32* bitcast (i24* getelementptr inbounds (%struct.m, %struct.m* @k, i64 0, i32 0, i32 1) to i32*), align 4
+  %0 = load i16, i16* @c, align 2
+  %conv = sext i16 %0 to i32
+  %1 = load i16, i16* @b, align 2
+  %conv1 = sext i16 %1 to i32
+  %2 = load i32, i32* @a, align 4
+  %tobool = icmp ne i32 %2, 0
+  %bf.load3 = load i32, i32* getelementptr inbounds (%struct.i, %struct.i* @l, i64 0, i32 0), align 4
+  %bf.shl = shl i32 %bf.load3, 7
+  %bf.ashr = ashr exact i32 %bf.shl, 7
+  %bf.clear = shl i32 %bf.load, 1
+  %factor = and i32 %bf.clear, 131070
+  %add13 = add nsw i32 %factor, %conv
+  %add15 = add nsw i32 %add13, %conv1
+  %bf.ashr.op = sub nsw i32 0, %bf.ashr
+  %add28 = select i1 %tobool, i32 %bf.ashr.op, i32 0
+  %tobool29 = icmp eq i32 %add15, %add28
+  %phitmp = icmp eq i32 %bf.ashr, 0
+  %.phitmp = or i1 %phitmp, %tobool29
+  %conv37 = zext i1 %.phitmp to i16
+  store i16 %conv37, i16* @e, align 2
+  %bf.clear39 = and i32 %bf.load, 65535
+  %factor53 = shl nuw nsw i32 %bf.clear39, 1
+  %add46 = add nsw i32 %factor53, %conv
+  %add48 = add nsw i32 %add46, %conv1
+  %add48.lobit = lshr i32 %add48, 31
+  %add48.lobit.not = xor i32 %add48.lobit, 1
+  %add51 = add nuw nsw i32 %add48.lobit.not, %bf.clear39
+  %shr = ashr i32 %2, %add51
+  %conv52 = trunc i32 %shr to i16
+  store i16 %conv52, i16* @b, align 2
+  ret void
+}
+
+; Test for PR31536
+define void @_Z2x6v() local_unnamed_addr {
+; CHECK-LABEL: _Z2x6v:
+entry:
+  %0 = load i32, i32* @x1, align 4
+  %and = and i32 %0, 511
+  %add = add nuw nsw i32 %and, 1
+  store i32 %add, i32* @x4, align 4
+  %.pr = load i32, i32* @x3, align 4
+  %tobool8 = icmp eq i32 %.pr, 0
+  br i1 %tobool8, label %for.end5, label %for.cond1thread-pre-split.lr.ph
+
+for.cond1thread-pre-split.lr.ph:                  ; preds = %entry
+  %idx.ext13 = zext i32 %add to i64
+  %x5.promoted = load double*, double** @x5, align 8
+  %x5.promoted9 = bitcast double* %x5.promoted to i8*
+  %1 = xor i32 %.pr, -1
+  %2 = zext i32 %1 to i64
+  %3 = shl nuw nsw i64 %2, 3
+  %4 = add nuw nsw i64 %3, 8
+  %5 = mul nuw nsw i64 %4, %idx.ext13
+  %uglygep = getelementptr i8, i8* %x5.promoted9, i64 %5
+  %.pr6.pre = load i32, i32* @x2, align 4
+  %6 = shl nuw nsw i32 %and, 3
+  %addconv = add nuw nsw i32 %6, 8
+  %7 = zext i32 %addconv to i64
+  %scevgep15 = getelementptr double, double* %x5.promoted, i64 1
+  %scevgep1516 = bitcast double* %scevgep15 to i8*
+  br label %for.cond1thread-pre-split
+
+for.cond1thread-pre-split:                        ; preds = %for.cond1thread-pre-split.lr.ph, %for.inc3
+  %indvar = phi i64 [ 0, %for.cond1thread-pre-split.lr.ph ], [ %indvar.next, %for.inc3 ]
+  %.pr6 = phi i32 [ %.pr6.pre, %for.cond1thread-pre-split.lr.ph ], [ %.pr611, %for.inc3 ]
+  %8 = phi double* [ %x5.promoted, %for.cond1thread-pre-split.lr.ph ], [ %add.ptr, %for.inc3 ]
+  %9 = phi i32 [ %.pr, %for.cond1thread-pre-split.lr.ph ], [ %inc4, %for.inc3 ]
+  %10 = mul i64 %7, %indvar
+  %uglygep14 = getelementptr i8, i8* %x5.promoted9, i64 %10
+  %uglygep17 = getelementptr i8, i8* %scevgep1516, i64 %10
+  %cmp7 = icmp slt i32 %.pr6, 0
+  br i1 %cmp7, label %for.body2.preheader, label %for.inc3
+
+for.body2.preheader:                              ; preds = %for.cond1thread-pre-split
+  %11 = sext i32 %.pr6 to i64
+  %12 = sext i32 %.pr6 to i64
+  %13 = icmp sgt i64 %12, -1
+  %smax = select i1 %13, i64 %12, i64 -1
+  %14 = add nsw i64 %smax, 1
+  %15 = sub nsw i64 %14, %12
+  %min.iters.check = icmp ult i64 %15, 4
+  br i1 %min.iters.check, label %for.body2.preheader21, label %min.iters.checked
+
+min.iters.checked:                                ; preds = %for.body2.preheader
+  %n.vec = and i64 %15, -4
+  %cmp.zero = icmp eq i64 %n.vec, 0
+  br i1 %cmp.zero, label %for.body2.preheader21, label %vector.memcheck
+
+vector.memcheck:                                  ; preds = %min.iters.checked
+  %16 = shl nsw i64 %11, 3
+  %scevgep = getelementptr i8, i8* %uglygep14, i64 %16
+  %17 = icmp sgt i64 %11, -1
+  %smax18 = select i1 %17, i64 %11, i64 -1
+  %18 = shl nsw i64 %smax18, 3
+  %scevgep19 = getelementptr i8, i8* %uglygep17, i64 %18
+  %bound0 = icmp ult i8* %scevgep, bitcast (double* @x0 to i8*)
+  %bound1 = icmp ugt i8* %scevgep19, bitcast (double* @x0 to i8*)
+  %memcheck.conflict = and i1 %bound0, %bound1
+  %ind.end = add nsw i64 %11, %n.vec
+  br i1 %memcheck.conflict, label %for.body2.preheader21, label %vector.body.preheader
+
+vector.body.preheader:                            ; preds = %vector.memcheck
+  %19 = add nsw i64 %n.vec, -4
+  %20 = lshr exact i64 %19, 2
+  %21 = and i64 %20, 1
+  %lcmp.mod = icmp eq i64 %21, 0
+  br i1 %lcmp.mod, label %vector.body.prol.preheader, label %vector.body.prol.loopexit.unr-lcssa
+
+vector.body.prol.preheader:                       ; preds = %vector.body.preheader
+  br label %vector.body.prol
+
+vector.body.prol:                                 ; preds = %vector.body.prol.preheader
+  %22 = load i64, i64* bitcast (double* @x0 to i64*), align 8
+  %23 = insertelement <2 x i64> undef, i64 %22, i32 0
+  %24 = shufflevector <2 x i64> %23, <2 x i64> undef, <2 x i32> zeroinitializer
+  %25 = insertelement <2 x i64> undef, i64 %22, i32 0
+  %26 = shufflevector <2 x i64> %25, <2 x i64> undef, <2 x i32> zeroinitializer
+  %27 = getelementptr inbounds double, double* %8, i64 %11
+  %28 = bitcast double* %27 to <2 x i64>*
+  store <2 x i64> %24, <2 x i64>* %28, align 8
+  %29 = getelementptr double, double* %27, i64 2
+  %30 = bitcast double* %29 to <2 x i64>*
+  store <2 x i64> %26, <2 x i64>* %30, align 8
+  br label %vector.body.prol.loopexit.unr-lcssa
+
+vector.body.prol.loopexit.unr-lcssa:              ; preds = %vector.body.preheader, %vector.body.prol
+  %index.unr.ph = phi i64 [ 4, %vector.body.prol ], [ 0, %vector.body.preheader ]
+  br label %vector.body.prol.loopexit
+
+vector.body.prol.loopexit:                        ; preds = %vector.body.prol.loopexit.unr-lcssa
+  %31 = icmp eq i64 %20, 0
+  br i1 %31, label %middle.block, label %vector.body.preheader.new
+
+vector.body.preheader.new:                        ; preds = %vector.body.prol.loopexit
+  %32 = load i64, i64* bitcast (double* @x0 to i64*), align 8
+  %33 = insertelement <2 x i64> undef, i64 %32, i32 0
+  %34 = shufflevector <2 x i64> %33, <2 x i64> undef, <2 x i32> zeroinitializer
+  %35 = insertelement <2 x i64> undef, i64 %32, i32 0
+  %36 = shufflevector <2 x i64> %35, <2 x i64> undef, <2 x i32> zeroinitializer
+  %37 = load i64, i64* bitcast (double* @x0 to i64*), align 8
+  %38 = insertelement <2 x i64> undef, i64 %37, i32 0
+  %39 = shufflevector <2 x i64> %38, <2 x i64> undef, <2 x i32> zeroinitializer
+  %40 = insertelement <2 x i64> undef, i64 %37, i32 0
+  %41 = shufflevector <2 x i64> %40, <2 x i64> undef, <2 x i32> zeroinitializer
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.body.preheader.new
+  %index = phi i64 [ %index.unr.ph, %vector.body.preheader.new ], [ %index.next.1, %vector.body ]
+  %42 = add i64 %11, %index
+  %43 = getelementptr inbounds double, double* %8, i64 %42
+  %44 = bitcast double* %43 to <2 x i64>*
+  store <2 x i64> %34, <2 x i64>* %44, align 8
+  %45 = getelementptr double, double* %43, i64 2
+  %46 = bitcast double* %45 to <2 x i64>*
+  store <2 x i64> %36, <2 x i64>* %46, align 8
+  %index.next = add i64 %index, 4
+  %47 = add i64 %11, %index.next
+  %48 = getelementptr inbounds double, double* %8, i64 %47
+  %49 = bitcast double* %48 to <2 x i64>*
+  store <2 x i64> %39, <2 x i64>* %49, align 8
+  %50 = getelementptr double, double* %48, i64 2
+  %51 = bitcast double* %50 to <2 x i64>*
+  store <2 x i64> %41, <2 x i64>* %51, align 8
+  %index.next.1 = add i64 %index, 8
+  %52 = icmp eq i64 %index.next.1, %n.vec
+  br i1 %52, label %middle.block.unr-lcssa, label %vector.body
+
+middle.block.unr-lcssa:                           ; preds = %vector.body
+  br label %middle.block
+
+middle.block:                                     ; preds = %vector.body.prol.loopexit, %middle.block.unr-lcssa
+  %cmp.n = icmp eq i64 %15, %n.vec
+  br i1 %cmp.n, label %for.cond1.for.inc3_crit_edge, label %for.body2.preheader21
+
+for.body2.preheader21:                            ; preds = %middle.block, %vector.memcheck, %min.iters.checked, %for.body2.preheader
+  %indvars.iv.ph = phi i64 [ %11, %vector.memcheck ], [ %11, %min.iters.checked ], [ %11, %for.body2.preheader ], [ %ind.end, %middle.block ]
+  br label %for.body2
+
+for.body2:                                        ; preds = %for.body2.preheader21, %for.body2
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body2 ], [ %indvars.iv.ph, %for.body2.preheader21 ]
+  %53 = load i64, i64* bitcast (double* @x0 to i64*), align 8
+  %arrayidx = getelementptr inbounds double, double* %8, i64 %indvars.iv
+  %54 = bitcast double* %arrayidx to i64*
+  store i64 %53, i64* %54, align 8
+  %indvars.iv.next = add nsw i64 %indvars.iv, 1
+  %cmp = icmp slt i64 %indvars.iv, -1
+  br i1 %cmp, label %for.body2, label %for.cond1.for.inc3_crit_edge.loopexit
+
+for.cond1.for.inc3_crit_edge.loopexit:            ; preds = %for.body2
+  br label %for.cond1.for.inc3_crit_edge
+
+for.cond1.for.inc3_crit_edge:                     ; preds = %for.cond1.for.inc3_crit_edge.loopexit, %middle.block
+  %indvars.iv.next.lcssa = phi i64 [ %ind.end, %middle.block ], [ %indvars.iv.next, %for.cond1.for.inc3_crit_edge.loopexit ]
+  %55 = trunc i64 %indvars.iv.next.lcssa to i32
+  store i32 %55, i32* @x2, align 4
+  br label %for.inc3
+
+for.inc3:                                         ; preds = %for.cond1.for.inc3_crit_edge, %for.cond1thread-pre-split
+  %.pr611 = phi i32 [ %55, %for.cond1.for.inc3_crit_edge ], [ %.pr6, %for.cond1thread-pre-split ]
+  %inc4 = add nsw i32 %9, 1
+  %add.ptr = getelementptr inbounds double, double* %8, i64 %idx.ext13
+  %tobool = icmp eq i32 %inc4, 0
+  %indvar.next = add i64 %indvar, 1
+  br i1 %tobool, label %for.cond.for.end5_crit_edge, label %for.cond1thread-pre-split
+
+for.cond.for.end5_crit_edge:                      ; preds = %for.inc3
+  store i8* %uglygep, i8** bitcast (double** @x5 to i8**), align 8
+  store i32 0, i32* @x3, align 4
+  br label %for.end5
+
+for.end5:                                         ; preds = %for.cond.for.end5_crit_edge, %entry
+  ret void
+}
+