diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp | 3 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopUnroll/peel-loop-negative.ll | 28 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopUnroll/peel-loop-not-forced.ll | 2 |
3 files changed, 31 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp b/llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp index 73c14f5606b..a5f2765e1a3 100644 --- a/llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp +++ b/llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp @@ -82,7 +82,8 @@ void llvm::computePeelCount(Loop *L, unsigned LoopSize, // its only back edge. If there is such Phi, peeling 1 iteration from the // loop is profitable, because starting from 2nd iteration we will have an // invariant instead of this Phi. - if (LoopSize <= UP.Threshold) { + // First, check that we can peel at least one iteration. + if (2 * LoopSize <= UP.Threshold && UnrollPeelMaxCount > 0) { BasicBlock *BackEdge = L->getLoopLatch(); assert(BackEdge && "Loop is not in simplified form?"); BasicBlock *Header = L->getHeader(); diff --git a/llvm/test/Transforms/LoopUnroll/peel-loop-negative.ll b/llvm/test/Transforms/LoopUnroll/peel-loop-negative.ll new file mode 100644 index 00000000000..eab609a3002 --- /dev/null +++ b/llvm/test/Transforms/LoopUnroll/peel-loop-negative.ll @@ -0,0 +1,28 @@ +; RUN: opt < %s -S -loop-unroll -unroll-threshold=800 -unroll-peel-max-count=0 | FileCheck %s + +; We should not peel this loop even though we can, because the max count is set +; to zero. +define i32 @invariant_backedge_neg_1(i32 %a, i32 %b) { +; CHECK-LABEL: @invariant_backedge_neg_1 +; CHECK-NOT loop.peel{{.*}}: +; CHECK: loop: +; CHECK: %i = phi +; CHECK: %sum = phi +; CHECK: %plus = phi +entry: + br label %loop + +loop: + %i = phi i32 [ 0, %entry ], [ %inc, %loop ] + %sum = phi i32 [ 0, %entry ], [ %incsum, %loop ] + %plus = phi i32 [ %a, %entry ], [ %b, %loop ] + + %incsum = add i32 %sum, %plus + %inc = add i32 %i, 1 + %cmp = icmp slt i32 %i, 1000 + + br i1 %cmp, label %loop, label %exit + +exit: + ret i32 %sum +} diff --git a/llvm/test/Transforms/LoopUnroll/peel-loop-not-forced.ll b/llvm/test/Transforms/LoopUnroll/peel-loop-not-forced.ll index 3dcac87f824..c3cbbf1ca0c 100644 --- a/llvm/test/Transforms/LoopUnroll/peel-loop-not-forced.ll +++ b/llvm/test/Transforms/LoopUnroll/peel-loop-not-forced.ll @@ -1,4 +1,4 @@ -; RUN: opt < %s -S -loop-unroll -unroll-threshold=4 | FileCheck %s +; RUN: opt < %s -S -loop-unroll -unroll-threshold=8 | FileCheck %s define i32 @invariant_backedge_1(i32 %a, i32 %b) { ; CHECK-LABEL: @invariant_backedge_1 |
