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| author | Nate Begeman <natebegeman@mac.com> | 2010-12-17 23:12:19 +0000 |
|---|---|---|
| committer | Nate Begeman <natebegeman@mac.com> | 2010-12-17 23:12:19 +0000 |
| commit | 7aa18bf46ae5123f418f7316939a1b7d9f371ebc (patch) | |
| tree | 51c8c3a4ffdb595d25d1b8bffcde32bb79a50e1c /llvm/lib/Analysis/ValueTracking.cpp | |
| parent | 3fff1fd49bac4196c89eb9c2f1dc8a90840338c5 (diff) | |
| download | llvm-7aa18bf46ae5123f418f7316939a1b7d9f371ebc.zip llvm-7aa18bf46ae5123f418f7316939a1b7d9f371ebc.tar.gz llvm-7aa18bf46ae5123f418f7316939a1b7d9f371ebc.tar.bz2 | |
Add vector versions of some existing scalar transforms to aid codegen in matching psign & pblend operations to the IR produced by clang/gcc for their C idioms.
llvm-svn: 122105
Diffstat (limited to 'llvm/lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ValueTracking.cpp | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 7506295..f8145cd 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -678,6 +678,13 @@ unsigned llvm::ComputeNumSignBits(Value *V, const TargetData *TD, Tmp += C->getZExtValue(); if (Tmp > TyBits) Tmp = TyBits; } + // vector ashr X, <C, C, C, C> -> adds C sign bits + if (ConstantVector *C = dyn_cast<ConstantVector>(U->getOperand(1))) { + if (ConstantInt *CI = dyn_cast_or_null<ConstantInt>(C->getSplatValue())) { + Tmp += CI->getZExtValue(); + if (Tmp > TyBits) Tmp = TyBits; + } + } return Tmp; case Instruction::Shl: if (ConstantInt *C = dyn_cast<ConstantInt>(U->getOperand(1))) { |