Commit 1916a1c5 authored by Florian Hahn's avatar Florian Hahn Committed by Tom Stellard
Browse files

[VPlan] Fix crash caused by not updating all users properly. 

Users of VPValues are managed in a vector, so we need to be more
careful when iterating over users while updating them. For now, just
copy them.

Fixes 51798.

(cherry picked from commit 368af755)
parent 2aa67b31

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

+5 −2
Original line number Diff line number Diff line
@@ -234,12 +234,15 @@ bool VPlanTransforms::mergeReplicateRegions(VPlan &Plan) { 
    for (VPRecipeBase &Phi1ToMove : make_early_inc_range(reverse(*Merge1))) {

      VPValue *PredInst1 =

          cast<VPPredInstPHIRecipe>(&Phi1ToMove)->getOperand(0);

      for (VPUser *U : Phi1ToMove.getVPSingleValue()->users()) {

      VPValue *Phi1ToMoveV = Phi1ToMove.getVPSingleValue();

      SmallVector<VPUser *> Users(Phi1ToMoveV->user_begin(),

                                  Phi1ToMoveV->user_end());

      for (VPUser *U : Users) {

        auto *UI = dyn_cast<VPRecipeBase>(U);

        if (!UI || UI->getParent() != Then2)

          continue;

        for (unsigned I = 0, E = U->getNumOperands(); I != E; ++I) {

          if (Phi1ToMove.getVPSingleValue() != U->getOperand(I))

          if (Phi1ToMoveV != U->getOperand(I))

            continue;

          U->setOperand(I, PredInst1);

        }

llvm/test/Transforms/LoopVectorize/vplan-sink-scalars-and-merge.ll

+66 −0
Original line number Diff line number Diff line
@@ -836,3 +836,69 @@ loop: 
exit:

  ret void

}



define void @update_multiple_users(i16* noalias %src, i8* noalias %dst, i1 %c) {

; CHECK-LABEL: LV: Checking a loop in "update_multiple_users"

; CHECK:      VPlan 'Initial VPlan for VF={2},UF>=1' {

; CHECK-NEXT: loop.header:

; CHECK-NEXT:   WIDEN-INDUCTION %iv = phi 0, %iv.next

; CHECK-NEXT: Successor(s): loop.then

; CHECK-EMPTY:

; CHECK-NEXT: loop.then:

; CHECK-NEXT: Successor(s): loop.then.0

; CHECK-EMPTY:

; CHECK-NEXT: loop.then.0:

; CHECK-NEXT: Successor(s): pred.store

; CHECK-EMPTY:

; CHECK-NEXT: <xVFxUF> pred.store: {

; CHECK-NEXT:   pred.store.entry:

; CHECK-NEXT:     BRANCH-ON-MASK ir<%c>

; CHECK-NEXT:   Successor(s): pred.store.if, pred.store.continue

; CHECK-NEXT:   CondBit: ir<%c>

; CHECK-EMPTY:

; CHECK-NEXT:   pred.store.if:

; CHECK-NEXT:     REPLICATE ir<%l1> = load ir<%src>

; CHECK-NEXT:     REPLICATE ir<%cmp> = icmp ir<%l1>, ir<0>

; CHECK-NEXT:     REPLICATE ir<%l2> = trunc ir<%l1>

; CHECK-NEXT:     REPLICATE ir<%sel> = select ir<%cmp>, ir<5>, ir<%l2>

; CHECK-NEXT:     REPLICATE store ir<%sel>, ir<%dst>

; CHECK-NEXT:   Successor(s): pred.store.continue

; CHECK-EMPTY:

; CHECK-NEXT:   pred.store.continue:

; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%6> = ir<%l1>

; CHECK-NEXT:   No successors

; CHECK-NEXT: }

; CHECK-NEXT: Successor(s): loop.then.1

; CHECK-EMPTY:

; CHECK-NEXT: loop.then.1:

; CHECK-NEXT:   WIDEN ir<%sext.l1> = sext vp<%6>

; CHECK-NEXT: Successor(s): loop.latch

; CHECK-EMPTY:

; CHECK-NEXT: loop.latch:

; CHECK-NEXT: No successors

; CHECK-NEXT: }

;

entry:

  br label %loop.header



loop.header:

  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]

  br i1 %c, label %loop.then, label %loop.latch



loop.then:

  %l1 = load i16, i16* %src, align 2

  %l2 = trunc i16 %l1 to i8

  %cmp = icmp eq i16 %l1, 0

  %sel = select i1 %cmp, i8 5, i8 %l2

  store i8 %sel, i8* %dst, align 1

  %sext.l1 = sext i16 %l1 to i32

  br label %loop.latch



loop.latch:

  %iv.next = add nsw i64 %iv, 1

  %ec = icmp eq i64 %iv.next, 999

  br i1 %ec, label %exit, label %loop.header



exit:

  ret void

}