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adding support of shl instruction in lExtractConstantOffset optimization

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This commit is contained in:
Ilia Filippov
2013-12-16 15:11:13 +04:00
parent 8766e44b95
commit b5dc78b06e
1 changed files with 27 additions and 0 deletions
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27
opt.cpp
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@@ -1479,6 +1479,33 @@ lExtractConstantOffset(llvm::Value *vec, llvm::Value **constOffset,
insertBefore);
return;
}
else if (bop->getOpcode() == llvm::Instruction::Shl) {
lExtractConstantOffset(op0, &c0, &v0, insertBefore);
lExtractConstantOffset(op1, &c1, &v1, insertBefore);
// Given the product of constant and variable terms, we have:
// (c0 + v0) * (2^(c1 + v1)) = c0 * 2^c1 * 2^v1 + v0 * 2^c1 * 2^v1
// We can optimize only if v1 == NULL.
if ((v1 != NULL) || (c0 == NULL) || (c1 == NULL)) {
*constOffset = NULL;
*variableOffset = vec;
}
else if (v0 == NULL) {
*constOffset = vec;
*variableOffset = NULL;
}
else {
*constOffset =
llvm::BinaryOperator::Create(llvm::Instruction::Shl, c0, c1,
LLVMGetName("shl", c0, c1),
insertBefore);
*variableOffset =
llvm::BinaryOperator::Create(llvm::Instruction::Shl, v0, c1,
LLVMGetName("shl", v0, c1),
insertBefore);
}
return;
}
else if (bop->getOpcode() == llvm::Instruction::Mul) {
lExtractConstantOffset(op0, &c0, &v0, insertBefore);
lExtractConstantOffset(op1, &c1, &v1, insertBefore);