diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp --- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp +++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp @@ -2173,6 +2173,9 @@ BasicBlock *ZeroPred = nullptr; BasicBlock *OnePred = nullptr; for (BasicBlock *P : predecessors(PredBB)) { + // If PredPred ends with IndirectBrInst, we can't handle it. + if (isa(P->getTerminator())) + continue; if (ConstantInt *CI = dyn_cast_or_null( evaluateOnPredecessorEdge(BB, P, Cond))) { if (CI->isZero()) { diff --git a/llvm/test/Transforms/JumpThreading/indirectbr-in-predpred.ll b/llvm/test/Transforms/JumpThreading/indirectbr-in-predpred.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Transforms/JumpThreading/indirectbr-in-predpred.ll @@ -0,0 +1,33 @@ +; RUN: opt -S < %s -jump-threading | FileCheck %s + +; CHECK: %indirect.goto.dest = select i1 %cmp, i8* blockaddress(@test1, %PredBB1), i8* blockaddress(@test1, %PredPredBB2) +; CHECK: indirectbr i8* %indirect.goto.dest, [label %PredBB1, label %PredPredBB2] +define i1 @test1(i32 %0) #0 { +PredPredBB1: + %cmp = icmp ne i32 %0, 0 + %1 = add i32 32, %0 + %indirect.goto.dest = select i1 %cmp, i8* blockaddress(@test1, %PredBB1), i8* blockaddress(@test1, %PredPredBB2) + indirectbr i8* %indirect.goto.dest, [label %PredBB1, label %PredPredBB2] + +PredPredBB2: ; preds = %PredPredBB1 + %cmp1 = icmp ne i32 %0, 1 + br i1 %cmp1, label %PredBB1, label %BB2 + +PredBB1: ; preds = %PredPredBB2, %PredPredBB1 + %num = phi i32 [ 0, %PredPredBB1 ], [ %1, %PredPredBB2 ] + %cmp2 = icmp eq i32 %1, 100 + br i1 %cmp2, label %BB1, label %BB2 + +BB1: ; preds = %PredBB1 + %cmp3 = icmp eq i32 %num, 0 + br i1 %cmp3, label %BB2, label %BB3 + +BB2: ; preds = %BB1, %PredBB1, %PredPredBB2 + %2 = or i1 %cmp, true + ret i1 %2 + +BB3: ; preds = %BB1 + ret i1 true +} + +attributes #0 = { nounwind }