SmallVector<std::pair<BasicBlock*, Value*>, 8> Values;
llvm::sort(Preds);
for (const PHINode &PN : BB.phis()) {
- // Ensure that PHI nodes have at least one entry!
- Assert(PN.getNumIncomingValues() != 0,
- "PHI nodes must have at least one entry. If the block is dead, "
- "the PHI should be removed!",
- &PN);
Assert(PN.getNumIncomingValues() == Preds.size(),
"PHINode should have one entry for each predecessor of its "
"parent basic block!",
--- /dev/null
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -lcssa -loop-rotate < %s | FileCheck %s
+
+; After rotate, the phi has no operands because it has no predecessors.
+; We might want to delete that instruction instead, but we do not
+; fail/assert by assuming that the phi is invalid IR.
+
+define void @PR48296(i1 %cond) {
+; CHECK-LABEL: @PR48296(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[LOOP:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: br i1 [[COND:%.*]], label [[INC:%.*]], label [[LOOP_BACKEDGE:%.*]]
+; CHECK: loop.backedge:
+; CHECK-NEXT: br label [[LOOP]]
+; CHECK: dead:
+; CHECK-NEXT: unreachable
+; CHECK: inc:
+; CHECK-NEXT: br label [[LOOP_BACKEDGE]]
+; CHECK: return:
+; CHECK-NEXT: [[R:%.*]] = phi i32
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %loop
+
+loop:
+ br i1 %cond, label %inc, label %loop
+
+dead: ; No predecessors!
+ br i1 %cond, label %inc, label %return
+
+inc:
+ br label %loop
+
+return:
+ %r = phi i32 [ undef, %dead ]
+ ret void
+}