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| author | Hal Finkel <hfinkel@anl.gov> | 2013-01-26 16:49:04 +0000 |
|---|---|---|
| committer | Hal Finkel <hfinkel@anl.gov> | 2013-01-26 16:49:04 +0000 |
| commit | ec5c3c2bd37828e9fbd913f5ac7b7f75711ddd59 (patch) | |
| tree | 596f73254fc5c24deb6ab2a9237a6cd592e838e9 /lib/Transforms | |
| parent | 7a8aba906416b6998347b52c3c08610fdc190638 (diff) | |
| download | llvm-ec5c3c2bd37828e9fbd913f5ac7b7f75711ddd59.tar.gz llvm-ec5c3c2bd37828e9fbd913f5ac7b7f75711ddd59.tar.bz2 llvm-ec5c3c2bd37828e9fbd913f5ac7b7f75711ddd59.tar.xz | |
BBVectorize: Add a additional comment about the cost computation
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173580 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Vectorize/BBVectorize.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/Transforms/Vectorize/BBVectorize.cpp b/lib/Transforms/Vectorize/BBVectorize.cpp index 411d7f6ba3..4bd11c6844 100644 --- a/lib/Transforms/Vectorize/BBVectorize.cpp +++ b/lib/Transforms/Vectorize/BBVectorize.cpp @@ -994,6 +994,12 @@ namespace { unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2); Type *VT1 = getVecTypeForPair(IT1, JT1), *VT2 = getVecTypeForPair(IT2, JT2); + + // Note that this procedure is incorrect for insert and extract element + // instructions (because combining these often results in a shuffle), + // but this cost is ignored (because insert and extract element + // instructions are assigned a zero depth factor and are not really + // fused in general). unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2); if (VCost > ICost + JCost) |