[Mips] Optimize (shift x (and y, BitWidth - 1)) to (shift x, y) #73889
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yingopq
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✅ With the latest revision this PR passed the C/C++ code formatter. |
yingopq
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topperc
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| const APInt &RHS = cast<ConstantSDNode>(N->getOperand(1))->getAPIntValue(); | ||
| if (RHS.countr_one() >= ShAmtBits) { | ||
| LLVM_DEBUG(dbgs() << DEBUG_TYPE << " Need optimize 'and & shl/srl/sra' and operand value bits is " << RHS.countr_one() << "\n"); |
yingopq
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Do optimization to turn x >> (shift & 31/63) into a single srlv instead of andi + srlv, since the mips variable shift instruction already implicitly masks the shift, like x86, wasm and AMDGPU. Copy the X86DAGToDAGISel::isUnneededShiftMask() function to MIPS for checking whether need combine two instructions to one.
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Hi @topperc, |
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@xgupta Thanks! |
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Do optimization to turn x >> (shift & 31/63) into a single srlv instead of andi + srlv, since the mips variable shift instruction already implicitly masks the shift, like x86, wasm and AMDGPU. Copy the X86DAGToDAGISel::isUnneededShiftMask() function to MIPS for checking whether need combine two instructions to one.