diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 7 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopUnroll/pr14167.ll | 44 |
2 files changed, 49 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 3e062988823..148912b766b 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -3979,8 +3979,11 @@ getSmallConstantTripMultiple(Loop *L, BasicBlock *ExitingBlock) { ConstantInt *Result = MulC->getValue(); - // Guard against huge trip counts. - if (!Result || Result->getValue().getActiveBits() > 32) + // Guard against huge trip counts (this requires checking + // for zero to handle the case where the trip count == -1 and the + // addition wraps). + if (!Result || Result->getValue().getActiveBits() > 32 || + Result->getValue().getActiveBits() == 0) return 1; return (unsigned)Result->getZExtValue(); diff --git a/llvm/test/Transforms/LoopUnroll/pr14167.ll b/llvm/test/Transforms/LoopUnroll/pr14167.ll new file mode 100644 index 00000000000..205ae44b72e --- /dev/null +++ b/llvm/test/Transforms/LoopUnroll/pr14167.ll @@ -0,0 +1,44 @@ +; RUN: opt < %s -S -loop-unroll -unroll-runtime | FileCheck %s +target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32:64" +target triple = "powerpc64-bgq-linux" + +define void @test1() nounwind { +; Ensure that we don't crash when the trip count == -1. +; CHECK: @test1 +entry: + br label %for.cond2.preheader + +for.cond2.preheader: ; preds = %for.end, %entry + br i1 false, label %middle.block, label %vector.ph + +vector.ph: ; preds = %for.cond2.preheader + br label %vector.body + +vector.body: ; preds = %vector.body, %vector.ph + br i1 undef, label %middle.block.loopexit, label %vector.body + +middle.block.loopexit: ; preds = %vector.body + br label %middle.block + +middle.block: ; preds = %middle.block.loopexit, %for.cond2.preheader + br i1 true, label %for.end, label %scalar.preheader + +scalar.preheader: ; preds = %middle.block + br label %for.body4 + +for.body4: ; preds = %for.body4, %scalar.preheader + %indvars.iv = phi i64 [ 16000, %scalar.preheader ], [ %indvars.iv.next, %for.body4 ] + %indvars.iv.next = add i64 %indvars.iv, 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp ne i32 %lftr.wideiv, 16000 + br i1 %exitcond, label %for.body4, label %for.end.loopexit + +for.end.loopexit: ; preds = %for.body4 + br label %for.end + +for.end: ; preds = %for.end.loopexit, %middle.block + br i1 undef, label %for.cond2.preheader, label %for.end15 + +for.end15: ; preds = %for.end + ret void +} |
