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| author | Sanjoy Das <sanjoy@playingwithpointers.com> | 2015-06-06 05:24:10 +0000 |
|---|---|---|
| committer | Sanjoy Das <sanjoy@playingwithpointers.com> | 2015-06-06 05:24:10 +0000 |
| commit | ad714b1af3d57b18439f62f2a0a7b96798c2b62b (patch) | |
| tree | ee494f840941b9b9bb09368d72c34a6379e2449d /llvm/test/Transforms | |
| parent | 1c297e66fb839f574cfe2796acbcb8a499168259 (diff) | |
| download | bcm5719-llvm-ad714b1af3d57b18439f62f2a0a7b96798c2b62b.tar.gz bcm5719-llvm-ad714b1af3d57b18439f62f2a0a7b96798c2b62b.zip | |
[LoopUnroll] Fix truncation bug in canUnrollCompletely.
Summary:
canUnrollCompletely takes `unsigned` values for `UnrolledCost` and
`RolledDynamicCost` but is passed in `uint64_t`s that are silently
truncated. Because of this, when `UnrolledSize` is a large integer
that has a small remainder with UINT32_MAX, LLVM tries to completely
unroll loops with high trip counts.
Reviewers: mzolotukhin, chandlerc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10293
llvm-svn: 239218
Diffstat (limited to 'llvm/test/Transforms')
| -rw-r--r-- | llvm/test/Transforms/LoopUnroll/full-unroll-bad-cost.ll | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/llvm/test/Transforms/LoopUnroll/full-unroll-bad-cost.ll b/llvm/test/Transforms/LoopUnroll/full-unroll-bad-cost.ll new file mode 100644 index 00000000000..e5694fbeb0c --- /dev/null +++ b/llvm/test/Transforms/LoopUnroll/full-unroll-bad-cost.ll @@ -0,0 +1,58 @@ +; RUN: opt -S -loop-unroll < %s | FileCheck %s + +; LLVM should not try to fully unroll this loop. + +declare void @f() +declare void @g() +declare void @h() + +define void @trivial_loop() { +; CHECK-LABEL: @trivial_loop( + entry: + br label %loop + + loop: + %idx = phi i32 [ 0, %entry ], [ %idx.inc, %loop ] + %idx.inc = add i32 %idx, 1 + call void @f() + call void @g() + call void @h() + call void @f() + call void @g() + call void @h() + call void @f() + call void @g() + call void @h() + call void @f() + call void @g() + call void @h() + call void @f() + call void @g() + call void @h() + %be = icmp slt i32 %idx, 268435456 + br i1 %be, label %loop, label %exit + +; CHECK: loop: +; CHECK-NEXT: %idx = phi i32 [ 0, %entry ], [ %idx.inc, %loop ] +; CHECK-NEXT: %idx.inc = add i32 %idx, 1 +; CHECK-NEXT: call void @f() +; CHECK-NEXT: call void @g() +; CHECK-NEXT: call void @h() +; CHECK-NEXT: call void @f() +; CHECK-NEXT: call void @g() +; CHECK-NEXT: call void @h() +; CHECK-NEXT: call void @f() +; CHECK-NEXT: call void @g() +; CHECK-NEXT: call void @h() +; CHECK-NEXT: call void @f() +; CHECK-NEXT: call void @g() +; CHECK-NEXT: call void @h() +; CHECK-NEXT: call void @f() +; CHECK-NEXT: call void @g() +; CHECK-NEXT: call void @h() +; CHECK-NEXT: %be = icmp slt i32 %idx, 268435456 +; CHECK-NEXT: br i1 %be, label %loop, label %exit + + exit: + ret void +} |
