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| author | James Molloy <james.molloy@arm.com> | 2016-09-09 13:35:36 +0000 |
|---|---|---|
| committer | James Molloy <james.molloy@arm.com> | 2016-09-09 13:35:36 +0000 |
| commit | 57d9dfa9ac7618aea8de6d1d1d940db6c7474737 (patch) | |
| tree | 3ffd9c0c5df379168889f6cac3240cc838bc82fe /llvm/lib | |
| parent | 1454e90f86101a08445287635bf5c9b74497e1f7 (diff) | |
| download | bcm5719-llvm-57d9dfa9ac7618aea8de6d1d1d940db6c7474737.tar.gz bcm5719-llvm-57d9dfa9ac7618aea8de6d1d1d940db6c7474737.zip | |
[ARM] ADD with a negative offset can become SUB for free
So model that directly in TTI::getIntImmCost().
llvm-svn: 281044
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp index 13d57c0934a..10e6297ef1e 100644 --- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp +++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp @@ -73,6 +73,10 @@ int ARMTTIImpl::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm, // Conversion to BIC is free, and means we can use ~Imm instead. return std::min(getIntImmCost(Imm, Ty), getIntImmCost(~Imm, Ty)); + if (Opcode == Instruction::Add) + // Conversion to SUB is free, and means we can use -Imm instead. + return std::min(getIntImmCost(Imm, Ty), getIntImmCost(-Imm, Ty)); + if (Opcode == Instruction::ICmp && Imm.isNegative() && Ty->getIntegerBitWidth() == 32) { int64_t NegImm = -Imm.getSExtValue(); |
