[CodeGen] Cache Opcode in MachineInstr #96797
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This avoids the indirection through MCID when just accessing the opcode.
MaskRay
approved these changes
Jun 26, 2024
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I checked the best place for |
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We have a bunch of full bools in MachineInstr, does turning those into bitfields do anything? |
The only bools I see are in (out-of-line) ExtraInfo, which is not directly part of MachineInstr and not always allocated. |
cpiaseque
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Jul 3, 2024
This avoids the indirection through MCID when just accessing the opcode. This uses two of the four padding bytes at the end of MachineInstr.
AlexisPerry
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Jul 9, 2024
This avoids the indirection through MCID when just accessing the opcode. This uses two of the four padding bytes at the end of MachineInstr.
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This avoids the indirection through MCID when just accessing the opcode. This uses two of the four padding bytes at the end of MachineInstr.
http://llvm-compile-time-tracker.com/compare.php?from=54cb5ca9f48fc542b920662a0eee7c0e6f35bee0&to=b0f960613dd2188e2673663b9e8e38d2092e7d3f&stat=instructions:u
The actual performance impact might be slightly larger, as the MCID is less likely to be in cache than the MachineInstr.