Index: lib/Transforms/Utils/LoopVersioning.cpp =================================================================== --- lib/Transforms/Utils/LoopVersioning.cpp +++ lib/Transforms/Utils/LoopVersioning.cpp @@ -280,8 +280,9 @@ bool Changed = false; for (Loop *L : Worklist) { const LoopAccessInfo &LAI = LAA->getInfo(L); - if (L->isLoopSimplifyForm() && (LAI.getNumRuntimePointerChecks() || - !LAI.getPSE().getUnionPredicate().isAlwaysTrue())) { + if (L->isLoopSimplifyForm() && !LAI.hasConvergentOp() && + (LAI.getNumRuntimePointerChecks() || + !LAI.getPSE().getUnionPredicate().isAlwaysTrue())) { LoopVersioning LVer(LAI, L, LI, DT, SE); LVer.versionLoop(); LVer.annotateLoopWithNoAlias(); Index: test/Transforms/LoopVersioning/convergent.ll =================================================================== --- /dev/null +++ test/Transforms/LoopVersioning/convergent.ll @@ -0,0 +1,40 @@ +; RUN: opt -basicaa -loop-versioning -S < %s | FileCheck %s + +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" + +; Do not version this loop because of a convergent operation + +; CHECK-LABEL: @f( +; CHECK: call i32 @llvm.convergent( +; CHECK-NOT: call i32 @llvm.convergent( +define void @f(i32* %a, i32* %b, i32* %c) #0 { +entry: + br label %for.body + +for.body: ; preds = %for.body, %entry + %ind = phi i64 [ 0, %entry ], [ %add, %for.body ] + + %arrayidxA = getelementptr inbounds i32, i32* %a, i64 %ind + %loadA = load i32, i32* %arrayidxA, align 4 + + %arrayidxB = getelementptr inbounds i32, i32* %b, i64 %ind + %loadB = load i32, i32* %arrayidxB, align 4 + %convergentB = call i32 @llvm.convergent(i32 %loadB) + + %mulC = mul i32 %loadA, %convergentB + + %arrayidxC = getelementptr inbounds i32, i32* %c, i64 %ind + store i32 %mulC, i32* %arrayidxC, align 4 + + %add = add nuw nsw i64 %ind, 1 + %exitcond = icmp eq i64 %add, 20 + br i1 %exitcond, label %for.end, label %for.body + +for.end: ; preds = %for.body + ret void +} + +declare i32 @llvm.convergent(i32) #1 + +attributes #0 = { nounwind convergent } +attributes #1 = { nounwind readnone convergent }