JIT: Unblock Vector###<long> intrinsics on x86 #112728
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| // Keep casts with operands usable from memory. | ||
| if (castOp->isContained() || castOp->IsRegOptional()) | ||
| { | ||
| return op; | ||
| } |
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This condition, added in #72719, made this method effectively useless. Removing it was a zero-diff change. I can look in future at containing the casts rather than removing them.
| @@ -4677,19 +4539,16 @@ GenTree* Lowering::LowerHWIntrinsicCreate(GenTreeHWIntrinsic* node) | |||
| return LowerNode(node); | |||
| } | |||
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| GenTree* op2 = node->Op(2); | |||
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| // TODO-XArch-AVX512 : Merge the NI_Vector512_Create and NI_Vector256_Create paths below. | |||
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The churn in this section is just taking care of this TODO
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| assert(comp->compIsaSupportedDebugOnly(InstructionSet_SSE2)); | ||
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| tmp2 = InsertNewSimdCreateScalarUnsafeNode(TYP_SIMD16, op2, simdBaseJitType, 16); | ||
| LowerNode(tmp2); | ||
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| node->ResetHWIntrinsicId(NI_SSE_MoveLowToHigh, tmp1, tmp2); |
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Changing this to UnpackLow shows up as a regression in a few places, because movlhps is one byte smaller, but it enables other optimizations since unpcklpd takes a memory operand plus mask and embedded broadcast.
Vector128.Create(double, 1.0):
- vmovups xmm0, xmmword ptr [reloc @RWD00]
- vmovlhps xmm0, xmm1, xmm0
+ vunpcklpd xmm0, xmm1, qword ptr [reloc @RWD00] {1to2}| if (varDsc->lvIsParam) | ||
| { | ||
| // Promotion blocks combined read optimizations for SIMD loads of long params | ||
| return; | ||
| } |
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In isolation, this change produced a small number of diffs and was mostly an improvement. A few regressions show up in the SPMI reports, but the overall impact is good, especially considering the places we can load a long to vector with movq
This resolves a large number of TODOs around HWIntrinsic expansion involving scalar longs on x86.
The most significant change here is in promoting
CreateScalarandToScalarto code generating intrinsics instead of converting them to other intrinsics at lowering. This was necessary in order to handle emittingmovqfor scalar long loads/stores but also unlocks several other optimizations since we can now allowCreateScalarandToScalarto be contained and can specialize codegen depending on whether they end up loading/storing from/to memory or not. Some example improvements on x64:Vector128.CreateScalar(ref float):Vector128.CreateScalar(ref double):Vector128.CreateScalarUnsafe(ref short):ref byte b = Vector128<byte>.ToScalar():And the less realistic, but still interesting
Sse.AddScalar(Vector128.CreateScalar(ref float), Vector128.CreateScalar(ref float)).ToScalar():x86 diffs are much more significant, because of the newly-enabled intrinsic expansion: