diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopPredication.cpp | 4 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopPredication/basic.ll | 26 |
2 files changed, 28 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopPredication.cpp b/llvm/lib/Transforms/Scalar/LoopPredication.cpp index 017bf21d233..ed715d36984 100644 --- a/llvm/lib/Transforms/Scalar/LoopPredication.cpp +++ b/llvm/lib/Transforms/Scalar/LoopPredication.cpp @@ -850,7 +850,7 @@ Optional<LoopICmp> LoopPredication::parseLoopLatchICmp() { } auto *BI = dyn_cast<BranchInst>(LoopLatch->getTerminator()); - if (!BI) { + if (!BI || !BI->isConditional()) { LLVM_DEBUG(dbgs() << "Failed to match the latch terminator!\n"); return None; } @@ -860,7 +860,7 @@ Optional<LoopICmp> LoopPredication::parseLoopLatchICmp() { "One of the latch's destinations must be the header"); auto *ICI = dyn_cast<ICmpInst>(BI->getCondition()); - if (!ICI || !BI->isConditional()) { + if (!ICI) { LLVM_DEBUG(dbgs() << "Failed to match the latch condition!\n"); return None; } diff --git a/llvm/test/Transforms/LoopPredication/basic.ll b/llvm/test/Transforms/LoopPredication/basic.ll index 6f294b5b67e..88fa1bb95b2 100644 --- a/llvm/test/Transforms/LoopPredication/basic.ll +++ b/llvm/test/Transforms/LoopPredication/basic.ll @@ -1853,3 +1853,29 @@ exit: ret i32 0 } +; Negative test, make sure we don't crash on unconditional latches +; TODO: there's no reason we shouldn't be able to predicate the +; condition for an statically infinite loop. +define i32 @unconditional_latch(i32* %a, i32 %length) { +; CHECK-LABEL: @unconditional_latch( +; CHECK-NEXT: loop.preheader: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[LOOP]] ], [ 400, [[LOOP_PREHEADER:%.*]] ] +; CHECK-NEXT: [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[I]], [[LENGTH:%.*]] +; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[WITHIN_BOUNDS]], i32 9) [ "deopt"() ] +; CHECK-NEXT: store volatile i32 0, i32* [[A:%.*]] +; CHECK-NEXT: [[I_NEXT]] = add i32 [[I]], 1 +; CHECK-NEXT: br label [[LOOP]] +; +loop.preheader: + br label %loop + +loop: + %i = phi i32 [ %i.next, %loop ], [ 400, %loop.preheader ] + %within.bounds = icmp ult i32 %i, %length + call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ] + store volatile i32 0, i32* %a + %i.next = add i32 %i, 1 + br label %loop +} |
