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 it's one byte larger, but it enables other optimizations since unpcklpd takes a memory operand and movlhps doesn't:
- movups xmm0, xmmword ptr [reloc @RWD00]
- movlhps xmm1, xmm0
+ unpcklpd xmm1, xmmword ptr [reloc @RWD00]| 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
The primary motivation here is resolving the many TODOs around HWIntrinsics involving scalar longs on x86. We're currently blocking a lot of intrinsics from expansion because of inability to handle long values.
The most significant change here is in promoting
CreateScalarandToScalarto code generating intrinsics instead of converting them to other intrinsics at lowering. This unblocks several 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: