[X86][Costmodel] Load/store i8 Stride=2 VF=8 interleaving costs

The only sched models that for cpu's that support avx2
but not avx512 are: haswell, broadwell, skylake, zen1-3

Identical to VF=2.

For load we have:
https://godbolt.org/z/4TEbdzbMM - for intels `Block RThroughput: =2.0`; for ryzens, `Block RThroughput: <=1.0`
So pick cost of `2`.

For store we have:
https://godbolt.org/z/MYfzGPf3Y - for intels `Block RThroughput: =1.0`; for ryzens, `Block RThroughput: <=0.5`
So pick cost of `1`.

I'm directly using the shuffling asm the llc produced,
without any manual fixups that may be needed
to ensure sequential execution.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D110705

llvm/lib/Target/X86/X86TargetTransformInfo.cpp

@@ -5065,6 +5065,7 @@ InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
   static const CostTblEntry AVX2InterleavedLoadTbl[] = {
       {2, MVT::v2i8, 2},  // (load 4i8 and) deinterleave into 2 x 2i8
       {2, MVT::v4i8, 2},  // (load 8i8 and) deinterleave into 2 x 4i8
+      {2, MVT::v8i8, 2},  // (load 16i8 and) deinterleave into 2 x 8i8
 
       {2, MVT::v2i16, 2}, // (load 4i16 and) deinterleave into 2 x 2i16
       {2, MVT::v4i16, 2}, // (load 8i16 and) deinterleave into 2 x 4i16
@@ -5105,6 +5106,7 @@ InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
   static const CostTblEntry AVX2InterleavedStoreTbl[] = {
       {2, MVT::v2i8, 1}, // interleave 2 x 2i8 into 4i8 (and store)
       {2, MVT::v4i8, 1}, // interleave 2 x 4i8 into 8i8 (and store)
+      {2, MVT::v8i8, 1}, // interleave 2 x 8i8 into 16i8 (and store)
 
       {2, MVT::v2i16, 1}, // interleave 2 x 2i16 into 4i16 (and store)
       {2, MVT::v4i16, 1}, // interleave 2 x 4i16 into 8i16 (and store)

llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll

@@ -28,7 +28,7 @@ target triple = "x86_64-unknown-linux-gnu"
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 3 for VF 2 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 3 for VF 4 For instruction:   %v0 = load i8, i8* %in0, align 1
-; AVX2: LV: Found an estimated cost of 33 for VF 8 For instruction:   %v0 = load i8, i8* %in0, align 1
+; AVX2: LV: Found an estimated cost of 3 for VF 8 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 81 for VF 16 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 166 for VF 32 For instruction:   %v0 = load i8, i8* %in0, align 1
 ;

llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll

@@ -28,7 +28,7 @@ target triple = "x86_64-unknown-linux-gnu"
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 2 for VF 2 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 2 for VF 4 For instruction:   store i8 %v1, i8* %out1, align 1
-; AVX2: LV: Found an estimated cost of 33 for VF 8 For instruction:   store i8 %v1, i8* %out1, align 1
+; AVX2: LV: Found an estimated cost of 2 for VF 8 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 67 for VF 16 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 166 for VF 32 For instruction:   store i8 %v1, i8* %out1, align 1
 ;