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Use ldp/stp with SIMD registers on Arm64 #84135

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Merged
merged 2 commits into from
Mar 31, 2023
Merged

Use ldp/stp with SIMD registers on Arm64 #84135

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Use ldp/stp with SIMD registers on Arm64
SwapnilGaikwad Mar 27, 2023
ac9548c
Incorporate review comments
SwapnilGaikwad Mar 31, 2023
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21 changes: 16 additions & 5 deletions src/coreclr/jit/emitarm64.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16248,6 +16248,12 @@ bool emitter::ReplaceLdrStrWithPairInstr(
// ldr w1, [x20, #0x14]
// ldr w2, [x20, #0x10] => ldp w2, w1, [x20, #0x10]
//
// ldr w1, [x20]
// ldr w2, [x20, #0x04] => ldp w1, w2, [x20]
//
// ldr q1, [x0, #0x20]
// ldr q2, [x0, #0x30] => ldp q1, q2, [x0, #0x20]
//
// Arguments:
// ins - The instruction code
// reg1 - Register 1 number
Expand Down Expand Up @@ -16291,16 +16297,21 @@ emitter::RegisterOrder emitter::IsOptimizableLdrStrWithPair(
return eRO_none;
}

if ((!isGeneralRegisterOrZR(reg1)) || (!isGeneralRegisterOrZR(prevReg1)))
if ((reg1 == REG_SP) || (prevReg1 == REG_SP) || (isGeneralRegisterOrZR(reg1) != isGeneralRegisterOrZR(prevReg1)))
{
// Either register 1 is not a general register or previous register 1 is not a general register
// or the zero register, so we cannot optimise.
// We cannot optimise when one of the following conditions are met
// 1. reg1 or prevReg1 is SP
// 2. both reg1 and prevReg1 are not of the same type (SIMD or non-SIMD)
return eRO_none;
}

if (lastInsFmt != fmt)
const bool compatibleFmt = (lastInsFmt == fmt) || (lastInsFmt == IF_LS_2B && fmt == IF_LS_2A) ||
(lastInsFmt == IF_LS_2A && fmt == IF_LS_2B);
if (!compatibleFmt)
{
// The formats of the two instructions differ.
// We cannot optimise when all of the following conditions are met
// 1. instruction formats differ
// 2. instructions are not using "base" or "base plus immediate offset" addressing modes
return eRO_none;
}

Expand Down