diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp index 81c81e441d7e3..bb5c5a4514ee1 100644 --- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -7640,6 +7640,10 @@ static bool processLoopInVPlanNativePath( OptimizationRemarkEmitter *ORE, BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI, LoopVectorizeHints &Hints) { + if (PSE.getBackedgeTakenCount() == PSE.getSE()->getCouldNotCompute()) { + LLVM_DEBUG(dbgs() << "LV: cannot compute the outer-loop trip count\n"); + return false; + } assert(EnableVPlanNativePath && "VPlan-native path is disabled."); Function *F = L->getHeader()->getParent(); InterleavedAccessInfo IAI(PSE, L, DT, LI, LVL->getLAI()); diff --git a/llvm/test/Transforms/LoopVectorize/vplan-outer-loop-uncomputable-trip-count.ll b/llvm/test/Transforms/LoopVectorize/vplan-outer-loop-uncomputable-trip-count.ll new file mode 100644 index 0000000000000..817d0b00ffca8 --- /dev/null +++ b/llvm/test/Transforms/LoopVectorize/vplan-outer-loop-uncomputable-trip-count.ll @@ -0,0 +1,47 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt -loop-vectorize -enable-vplan-native-path -S %s | FileCheck %s + +declare i1 @cond() + +; Make sure we do not vectorize (or crash) on outer loops with uncomputable +; trip-counts. + +define void @test() { +; CHECK-LABEL: @test( +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[FOR1_HEADER:%.*]] +; CHECK: for1.header: +; CHECK-NEXT: br label [[FOR2_HEADER:%.*]] +; CHECK: for2.header: +; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ 0, [[FOR1_HEADER]] ], [ [[INDVARS_IV_NEXT:%.*]], [[FOR2_HEADER]] ] +; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1 +; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], 0 +; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR1_LATCH:%.*]], label [[FOR2_HEADER]] +; CHECK: for1.latch: +; CHECK-NEXT: [[C:%.*]] = call i1 @cond() +; CHECK-NEXT: br i1 [[C]], label [[EXIT:%.*]], label [[FOR1_HEADER]], !llvm.loop !0 +; CHECK: exit: +; CHECK-NEXT: ret void +; +entry: + br label %for1.header + +for1.header: ; preds = %for.cond.cleanup3, %for.cond1.preheader.lr.ph + br label %for2.header + +for2.header: ; preds = %for.body10, %for.body10.preheader + %indvars.iv = phi i64 [ 0, %for1.header ], [ %indvars.iv.next, %for2.header ] + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 + %exitcond = icmp eq i64 %indvars.iv.next, 0 + br i1 %exitcond, label %for1.latch, label %for2.header + +for1.latch: ; preds = %for.cond.cleanup9 + %c = call i1 @cond() + br i1 %c, label %exit, label %for1.header, !llvm.loop !0 + +exit: ; preds = %for.cond.cleanup3, %entry + ret void +} + +!0 = distinct !{!0, !1} +!1 = !{!"llvm.loop.vectorize.enable", i1 true}