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author | Eli Bendersky <eliben@google.com> | 2014-05-01 18:38:36 +0000 |
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committer | Eli Bendersky <eliben@google.com> | 2014-05-01 18:38:36 +0000 |
commit | 167a57ca452efbb014ebce7ecfa99501b5039611 (patch) | |
tree | 6a2b1de596c6e17369a85ab06e8bf0407bc07d83 /lib/Target/NVPTX | |
parent | 75bb54dcc55d1c206b37af9a91b8e479f9f75104 (diff) | |
download | llvm-167a57ca452efbb014ebce7ecfa99501b5039611.tar.gz llvm-167a57ca452efbb014ebce7ecfa99501b5039611.tar.bz2 llvm-167a57ca452efbb014ebce7ecfa99501b5039611.tar.xz |
Add an optimization that does CSE in a group of similar GEPs.
This optimization merges the common part of a group of GEPs, so we can compute
each pointer address by adding a simple offset to the common part.
The optimization is currently only enabled for the NVPTX backend, where it has
a large payoff on some benchmarks.
Review: http://reviews.llvm.org/D3462
Patch by Jingyue Wu.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207783 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/NVPTX')
-rw-r--r-- | lib/Target/NVPTX/NVPTXTargetMachine.cpp | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/lib/Target/NVPTX/NVPTXTargetMachine.cpp b/lib/Target/NVPTX/NVPTXTargetMachine.cpp index 0cc5c51629..26a4f84052 100644 --- a/lib/Target/NVPTX/NVPTXTargetMachine.cpp +++ b/lib/Target/NVPTX/NVPTXTargetMachine.cpp @@ -147,10 +147,23 @@ void NVPTXPassConfig::addIRPasses() { addPass(createNVPTXAssignValidGlobalNamesPass()); addPass(createGenericToNVVMPass()); addPass(createNVPTXFavorNonGenericAddrSpacesPass()); - // The FavorNonGenericAddrSpaces pass may remove instructions and leave some - // values unused. Therefore, we run a DCE pass right afterwards. We could - // remove unused values in an ad-hoc manner, but it requires manual work and - // might be error-prone. + addPass(createSeparateConstOffsetFromGEPPass()); + // The SeparateConstOffsetFromGEP pass creates variadic bases that can be used + // by multiple GEPs. Run GVN or EarlyCSE to really reuse them. GVN generates + // significantly better code than EarlyCSE for some of our benchmarks. + if (getOptLevel() == CodeGenOpt::Aggressive) + addPass(createGVNPass()); + else + addPass(createEarlyCSEPass()); + // Both FavorNonGenericAddrSpaces and SeparateConstOffsetFromGEP may leave + // some dead code. We could remove dead code in an ad-hoc manner, but that + // requires manual work and might be error-prone. + // + // The FavorNonGenericAddrSpaces pass shortcuts unnecessary addrspacecasts, + // and leave them unused. + // + // SeparateConstOffsetFromGEP rebuilds a new index from the old index, and the + // old index and some of its intermediate results may become unused. addPass(createDeadCodeEliminationPass()); } |