// Now the loop blocks are cloned and the other exiting blocks from the
// remainder are connected to the original Loop's exit blocks. The remaining
// work is to update the phi nodes in the original loop, and take in the
- // values from the cloned region. Also update the dominator info for
- // OtherExits and their immediate successors, since we have new edges into
- // OtherExits.
- SmallPtrSet<BasicBlock*, 8> ImmediateSuccessorsOfExitBlocks;
+ // values from the cloned region.
for (auto *BB : OtherExits) {
for (auto &II : *BB) {
"Breaks the definition of dedicated exits!");
}
#endif
- // Update the dominator info because the immediate dominator is no longer the
- // header of the original Loop. BB has edges both from L and remainder code.
- // Since the preheader determines which loop is run (L or directly jump to
- // the remainder code), we set the immediate dominator as the preheader.
- if (DT) {
- DT->changeImmediateDominator(BB, PreHeader);
- // Also update the IDom for immediate successors of BB. If the current
- // IDom is the header, update the IDom to be the preheader because that is
- // the nearest common dominator of all predecessors of SuccBB. We need to
- // check for IDom being the header because successors of exit blocks can
- // have edges from outside the loop, and we should not incorrectly update
- // the IDom in that case.
- for (BasicBlock *SuccBB: successors(BB))
- if (ImmediateSuccessorsOfExitBlocks.insert(SuccBB).second) {
- if (DT->getNode(SuccBB)->getIDom()->getBlock() == Header) {
- assert(!SuccBB->getSinglePredecessor() &&
- "BB should be the IDom then!");
- DT->changeImmediateDominator(SuccBB, PreHeader);
- }
- }
+ }
+
+ // Update the immediate dominator of the exit blocks and blocks that are
+ // reachable from the exit blocks. This is needed because we now have paths
+ // from both the original loop and the remainder code reaching the exit
+ // blocks. While the IDom of these exit blocks were from the original loop,
+ // now the IDom is the preheader (which decides whether the original loop or
+ // remainder code should run).
+ if (DT && !L->getExitingBlock()) {
+ SmallVector<BasicBlock *, 16> ChildrenToUpdate;
+ // NB! We have to examine the dom children of all loop blocks, not just
+ // those which are the IDom of the exit blocks. This is because blocks
+ // reachable from the exit blocks can have their IDom as the nearest common
+ // dominator of the exit blocks.
+ for (auto *BB : L->blocks()) {
+ auto *DomNodeBB = DT->getNode(BB);
+ for (auto *DomChild : DomNodeBB->getChildren()) {
+ auto *DomChildBB = DomChild->getBlock();
+ if (!L->contains(LI->getLoopFor(DomChildBB)))
+ ChildrenToUpdate.push_back(DomChildBB);
+ }
}
+ for (auto *BB : ChildrenToUpdate)
+ DT->changeImmediateDominator(BB, PreHeader);
}
// Loop structure should be the following:
exitsucc: ; preds = %headerexit
ret i64 96
}
+
+; exit block (%default) has an exiting block and another exit block as predecessors.
+define void @test4(i16 %c3) {
+; CHECK-LABEL: test4
+
+; CHECK-LABEL: exiting.prol:
+; CHECK-NEXT: switch i16 %c3, label %default.loopexit.loopexit1 [
+
+; CHECK-LABEL: exiting:
+; CHECK-NEXT: switch i16 %c3, label %default.loopexit.loopexit [
+
+; CHECK-LABEL: default.loopexit.loopexit:
+; CHECK-NEXT: br label %default.loopexit
+
+; CHECK-LABEL: default.loopexit.loopexit1:
+; CHECK-NEXT: br label %default.loopexit
+
+; CHECK-LABEL: default.loopexit:
+; CHECK-NEXT: br label %default
+preheader:
+ %c1 = zext i32 undef to i64
+ br label %header
+
+header: ; preds = %latch, %preheader
+ %indvars.iv = phi i64 [ 0, %preheader ], [ %indvars.iv.next, %latch ]
+ br label %exiting
+
+exiting: ; preds = %header
+ switch i16 %c3, label %default [
+ i16 45, label %otherexit
+ i16 95, label %latch
+ ]
+
+latch: ; preds = %exiting
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %c2 = icmp ult i64 %indvars.iv.next, %c1
+ br i1 %c2, label %header, label %latchexit
+
+latchexit: ; preds = %latch
+ ret void
+
+default: ; preds = %otherexit, %exiting
+ ret void
+
+otherexit: ; preds = %exiting
+ br label %default
+}
+
+; exit block (%exitB) has an exiting block and another exit block as predecessors.
+; exiting block comes from inner loop.
+define void @test5() {
+; CHECK-LABEL: test5
+; CHECK-LABEL: bb1:
+; CHECK-NEXT: br i1 false, label %outerH.prol.preheader, label %outerH.prol.loopexit
+
+; CHECK-LABEL: outerH.prol.preheader:
+; CHECK-NEXT: br label %outerH.prol
+
+; CHECK-LABEL: outerH.prol:
+; CHECK-NEXT: %tmp4.prol = phi i32 [ %tmp6.prol, %outerLatch.prol ], [ undef, %outerH.prol.preheader ]
+; CHECK-NEXT: %prol.iter = phi i32 [ 0, %outerH.prol.preheader ], [ %prol.iter.sub, %outerLatch.prol ]
+; CHECK-NEXT: br label %innerH.prol
+bb:
+ %tmp = icmp sgt i32 undef, 79
+ br i1 %tmp, label %outerLatchExit, label %bb1
+
+bb1: ; preds = %bb
+ br label %outerH
+
+outerH: ; preds = %outerLatch, %bb1
+ %tmp4 = phi i32 [ %tmp6, %outerLatch ], [ undef, %bb1 ]
+ br label %innerH
+
+innerH: ; preds = %innerLatch, %outerH
+ br i1 undef, label %innerexiting, label %otherexitB
+
+innerexiting: ; preds = %innerH
+ br i1 undef, label %innerLatch, label %exitB
+
+innerLatch: ; preds = %innerexiting
+ %tmp13 = fcmp olt double undef, 2.000000e+00
+ br i1 %tmp13, label %innerH, label %outerLatch
+
+outerLatch: ; preds = %innerLatch
+ %tmp6 = add i32 %tmp4, 1
+ %tmp7 = icmp sgt i32 %tmp6, 79
+ br i1 %tmp7, label %outerLatchExit, label %outerH
+
+outerLatchExit: ; preds = %outerLatch, %bb
+ ret void
+
+exitB: ; preds = %innerexiting, %otherexitB
+ ret void
+
+otherexitB: ; preds = %innerH
+ br label %exitB
+
+}
+
+; Blocks reachable from exits (not_zero44) have the IDom as the block within the loop (Header).
+; Update the IDom to the preheader.
+define void @test6() {
+; CHECK-LABEL: test6
+; CHECK-LABEL: header.prol.preheader:
+; CHECK-NEXT: br label %header.prol
+
+; CHECK-LABEL: header.prol:
+; CHECK-NEXT: %indvars.iv.prol = phi i64 [ undef, %header.prol.preheader ], [ %indvars.iv.next.prol, %latch.prol ]
+; CHECK-NEXT: %prol.iter = phi i64 [ 1, %header.prol.preheader ], [ %prol.iter.sub, %latch.prol ]
+; CHECK-NEXT: br i1 false, label %latch.prol, label %otherexit.loopexit1
+
+; CHECK-LABEL: header.prol.loopexit.unr-lcssa:
+; CHECK-NEXT: %indvars.iv.unr.ph = phi i64 [ %indvars.iv.next.prol, %latch.prol ]
+; CHECK-NEXT: br label %header.prol.loopexit
+
+; CHECK-LABEL: header.prol.loopexit:
+; CHECK-NEXT: %indvars.iv.unr = phi i64 [ undef, %entry ], [ %indvars.iv.unr.ph, %header.prol.loopexit.unr-lcssa ]
+; CHECK-NEXT: br i1 true, label %latchexit, label %entry.new
+
+; CHECK-LABEL: entry.new:
+; CHECK-NEXT: br label %header
+entry:
+ br label %header
+
+header: ; preds = %latch, %entry
+ %indvars.iv = phi i64 [ undef, %entry ], [ %indvars.iv.next, %latch ]
+ br i1 undef, label %latch, label %otherexit
+
+latch: ; preds = %header
+ %indvars.iv.next = add nsw i64 %indvars.iv, 2
+ %0 = icmp slt i64 %indvars.iv.next, 616
+ br i1 %0, label %header, label %latchexit
+
+latchexit: ; preds = %latch
+ br label %latchexitsucc
+
+otherexit: ; preds = %header
+ br label %otherexitsucc
+
+otherexitsucc: ; preds = %otherexit
+ br label %not_zero44
+
+not_zero44: ; preds = %latchexitsucc, %otherexitsucc
+ unreachable
+
+latchexitsucc: ; preds = %latchexit
+ br label %not_zero44
+}
+
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