[X86][Costmodel] Load/store i8 Stride=4 VF=2 interleaving costs

While we already model this tuple, the values are divergent from reality, so fix them.

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

For load we have:
https://godbolt.org/z/KP6nn36zs - for intels `Block RThroughput: =4.0`; for ryzens, `Block RThroughput: <=2.0`
So pick cost of `4`.

For store we have:
https://godbolt.org/z/ov95zhrq6 - for intels `Block RThroughput: =4.0`; for ryzens, `Block RThroughput: <=2.0`
So pick cost of `4`.

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/D110966

Author: LebedevRI

llvm/lib/Target/X86/X86TargetTransformInfo.cpp

@@ -5094,7 +5094,7 @@ InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
 
       {3, MVT::v8i32, 17}, // (load 24i32 and) deinterleave into 3 x 8i32
 
-      {4, MVT::v2i8, 12},  // (load 8i8 and) deinterleave into 4 x 2i8
+      {4, MVT::v2i8, 4},  // (load 8i8 and) deinterleave into 4 x 2i8
       {4, MVT::v4i8, 4},   // (load 16i8 and) deinterleave into 4 x 4i8
       {4, MVT::v8i8, 20},  // (load 32i8 and) deinterleave into 4 x 8i8
       {4, MVT::v16i8, 39}, // (load 64i8 and) deinterleave into 4 x 16i8
@@ -5144,7 +5144,7 @@ InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
       {3, MVT::v16i8, 11}, // interleave 3 x 16i8 into 48i8 (and store)
       {3, MVT::v32i8, 13}, // interleave 3 x 32i8 into 96i8 (and store)
 
-      {4, MVT::v2i8, 12},  // interleave 4 x 2i8 into 8i8 (and store)
+      {4, MVT::v2i8, 4},  // interleave 4 x 2i8 into 8i8 (and store)
       {4, MVT::v4i8, 9},   // interleave 4 x 4i8 into 16i8 (and store)
       {4, MVT::v8i8, 10},  // interleave 4 x 8i8 into 32i8 (and store)
       {4, MVT::v16i8, 10}, // interleave 4 x 16i8 into 64i8 (and store)

llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-4.ll

@@ -26,7 +26,7 @@ target triple = "x86_64-unknown-linux-gnu"
 ; AVX1: LV: Found an estimated cost of 332 for VF 32 For instruction:   %v0 = load i8, i8* %in0, align 1
 ;
 ; 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 13 for VF 2 For instruction:   %v0 = load i8, i8* %in0, align 1
+; AVX2: LV: Found an estimated cost of 5 for VF 2 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 5 for VF 4 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 21 for VF 8 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 41 for VF 16 For instruction:   %v0 = load i8, i8* %in0, align 1

llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.ll

@@ -26,7 +26,7 @@ target triple = "x86_64-unknown-linux-gnu"
 ; AVX1: LV: Found an estimated cost of 332 for VF 32 For instruction:   store i8 %v3, i8* %out3, align 1
 ;
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   store i8 %v3, i8* %out3, align 1
-; AVX2: LV: Found an estimated cost of 13 for VF 2 For instruction:   store i8 %v3, i8* %out3, align 1
+; AVX2: LV: Found an estimated cost of 5 for VF 2 For instruction:   store i8 %v3, i8* %out3, align 1
 ; AVX2: LV: Found an estimated cost of 10 for VF 4 For instruction:   store i8 %v3, i8* %out3, align 1
 ; AVX2: LV: Found an estimated cost of 11 for VF 8 For instruction:   store i8 %v3, i8* %out3, align 1
 ; AVX2: LV: Found an estimated cost of 12 for VF 16 For instruction:   store i8 %v3, i8* %out3, align 1