9375962ac9
The vast majority of the following (very common) opcodes were always called with identical arguments: - `GIM_CheckType` for the root - `GIM_CheckRegBankForClass` for the root - `GIR_Copy` between the old and new root - `GIR_ConstrainSelectedInstOperands` on the new root - `GIR_BuildMI` to create the new root I added overloaded version of each opcode specialized for the root instructions. It always saves between 1 and 2 bytes per instance depending on the number of arguments specialized into the opcode. Some of these opcodes had between 5 and 15k occurences in the AArch64 GlobalISel Match Table. Additionally, the following opcodes are almost always used in the same sequence: - `GIR_EraseFromParent 0` + `GIR_Done` - `GIR_EraseRootFromParent_Done` has been created to do both. Saves 2 bytes per occurence. - `GIR_IsSafeToFold` was *always* called for each InsnID except 0. - Changed the opcode to take the number of instructions to check after `MI[0]` The savings from these are pretty neat. For `AArch64GenGlobalISel.inc`: - `AArch64InstructionSelector.cpp.o` goes down from 772kb to 704kb (-10% code size) - Self-reported MatchTable size goes from 420380 bytes to 352426 bytes (~ -17%) A smaller match table means a faster match table because we spend less time iterating and decoding. I don't have a solid measurement methodology for GlobalISel performance so I don't have precise numbers but I saw a few % of improvements in a simple testcase.
27 lines
1.3 KiB
TableGen
27 lines
1.3 KiB
TableGen
// RUN: llvm-tblgen %s -gen-global-isel -optimize-match-table=true -I %p/../../include -I %p/Common -o - | FileCheck %s
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include "llvm/Target/Target.td"
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include "GlobalISelEmitterCommon.td"
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def InstTwoOperands : I<(outs GPR32:$dst), (ins GPR32:$src1, GPR32:$src2), []>;
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def InstThreeOperands : I<(outs GPR32:$dst), (ins GPR32:$cond, GPR32:$src,GPR32:$src2), []>;
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// Make sure the GIM_CheckIsSameOperand check is not hoisted into the common header group
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// CHECK: GIM_Try, /*On fail goto*//*Label 1*/
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// CHECK-NEXT: GIM_RootCheckRegBankForClass, /*Op*/0, /*RC*/GIMT_Encode2(MyTarget::GPR32RegClassID),
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// CHECK-NOT: GIM_CheckIsSameOperand
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// CHECK-NEXT: GIM_Try, /*On fail goto*//*Label 2*/
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// CHECK: GIM_CheckIsSameOperand, /*MI*/0, /*OpIdx*/3, /*OtherMI*/2, /*OtherOpIdx*/1,
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// CHECK: // Label 2
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// CHECK-NEXT: GIM_Try, /*On fail goto*//*Label 3*/
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// CHECK: GIM_CheckIsSameOperand, /*MI*/0, /*OpIdx*/3, /*OtherMI*/2, /*OtherOpIdx*/2,
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// CHECK: // Label 1
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def : Pat<(i32 (select GPR32:$cond, GPR32:$src1, GPR32:$src2)),
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(InstThreeOperands GPR32:$cond, GPR32:$src1, GPR32:$src2)>;
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def : Pat<(i32 (select (i32 (setcc GPR32:$cond, (i32 0), (OtherVT SETEQ))),
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(i32 (add GPR32:$src1, GPR32:$const)),
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GPR32:$src1)),
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(InstThreeOperands GPR32:$cond, GPR32:$src1, GPR32:$const)>;
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