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| author | Wei Mi <wmi@google.com> | 2015-05-06 17:12:25 +0000 |
|---|---|---|
| committer | Wei Mi <wmi@google.com> | 2015-05-06 17:12:25 +0000 |
| commit | 062c74484d4788728a50db025a237db03f0cabe6 (patch) | |
| tree | 5eeac222e8b5db4826578ae00f2f424ef71b1eea /llvm/test/Transforms/LoopVectorize/unroll.ll | |
| parent | 633dba4f412fd7cfe0e1b5d7bdc60338e81beaf3 (diff) | |
| download | bcm5719-llvm-062c74484d4788728a50db025a237db03f0cabe6.tar.gz bcm5719-llvm-062c74484d4788728a50db025a237db03f0cabe6.zip | |
[X86] Disable loop unrolling in loop vectorization pass when VF is 1.
The patch disabled unrolling in loop vectorization pass when VF==1 on x86 architecture,
by setting MaxInterleaveFactor to 1. Unrolling in loop vectorization pass may introduce
the cost of overflow check, memory boundary check and extra prologue/epilogue code when
regular unroller will unroll the loop another time. Disable it when VF==1 remove the
unnecessary cost on x86. The same can be done for other platforms after verifying
interleaving/memory bound checking to be not perf critical on those platforms.
Differential Revision: http://reviews.llvm.org/D9515
llvm-svn: 236613
Diffstat (limited to 'llvm/test/Transforms/LoopVectorize/unroll.ll')
| -rw-r--r-- | llvm/test/Transforms/LoopVectorize/unroll.ll | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/llvm/test/Transforms/LoopVectorize/unroll.ll b/llvm/test/Transforms/LoopVectorize/unroll.ll new file mode 100644 index 00000000000..74076f69510 --- /dev/null +++ b/llvm/test/Transforms/LoopVectorize/unroll.ll @@ -0,0 +1,37 @@ +; This test makes sure that loop will not be unrolled in vectorization if VF computed +; equals to 1. +; RUN: opt < %s -loop-vectorize -S | FileCheck %s + +; Make sure there are no geps being merged. +; CHECK-LABEL: @foo( +; CHECK: getelementptr +; CHECK-NOT: getelementptr + +@N = common global i32 0, align 4 +@a = common global [1000 x i32] zeroinitializer, align 16 + +define void @foo() #0 { +entry: + %0 = load i32, i32* @N, align 4 + %cmp5 = icmp sgt i32 %0, 0 + br i1 %cmp5, label %for.body.lr.ph, label %for.end + +for.body.lr.ph: ; preds = %entry + %conv = sext i32 %0 to i64 + br label %for.body + +for.body: ; preds = %for.body.lr.ph, %for.body + %i.06 = phi i64 [ 0, %for.body.lr.ph ], [ %inc, %for.body ] + %mul = mul nuw nsw i64 %i.06, 7 + %arrayidx = getelementptr inbounds [1000 x i32], [1000 x i32]* @a, i64 0, i64 %mul + store i32 3, i32* %arrayidx, align 4 + %inc = add nuw nsw i64 %i.06, 1 + %cmp = icmp slt i64 %inc, %conv + br i1 %cmp, label %for.body, label %for.end.loopexit + +for.end.loopexit: ; preds = %for.body + br label %for.end + +for.end: ; preds = %for.end.loopexit, %entry + ret void +} |
