[X86][Costmodel] Load/store i16 Stride=2 VF=8 interleaving costs

[lebedev.ri]

Summary

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/e5YE99a4P - for intels Block RThroughput: =6.0; for ryzens, Block RThroughput: =2.0
So pick cost of 6.

For store we have:
https://godbolt.org/z/3vM4KsE1n - for intels Block RThroughput: =3.0; for ryzens, Block RThroughput: <=2.0
So pick cost of 3.

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

[RKSimon]

LGTM

llvm/lib/Target/X86/X86TargetTransformInfo.cpp

InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
   // sequence; The cost tables are therefore accessed with:
   // Factor (stride) and VectorType=VFxiN.
   // The Cost accounts only for the shuffle sequence;
   // The cost of the loads/stores is accounted for separately.
   //
   static const CostTblEntry AVX2InterleavedLoadTbl[] = {
       {2, MVT::v2i16, 2}, // (load 4i16 and) deinterleave into 2 x 2i16
       {2, MVT::v4i16, 2}, // (load 8i16 and) deinterleave into 2 x 4i16
+      {2, MVT::v8i16, 6}, // (load 16i16 and) deinterleave into 2 x 8i16
 
       {2, MVT::v4i64, 6}, // (load 8i64 and) deinterleave into 2 x 4i64
 
       {3, MVT::v2i8, 10},  // (load 6i8 and) deinterleave into 3 x 2i8
       {3, MVT::v4i8, 4},   // (load 12i8 and) deinterleave into 3 x 4i8
       {3, MVT::v8i8, 9},   // (load 24i8 and) deinterleave into 3 x 8i8
       {3, MVT::v16i8, 11}, // (load 48i8 and) deinterleave into 3 x 16i8
       {3, MVT::v32i8, 13}, // (load 96i8 and) deinterleave into 3 x 32i8
 
       {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::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
       {4, MVT::v32i8, 80}, // (load 128i8 and) deinterleave into 4 x 32i8
 
       {8, MVT::v8i32, 40} // (load 64i32 and) deinterleave into 8 x 8i32
   };
 
   static const CostTblEntry AVX2InterleavedStoreTbl[] = {
       {2, MVT::v2i16, 1}, // interleave 2 x 2i16 into 4i16 (and store)
       {2, MVT::v4i16, 1}, // interleave 2 x 4i16 into 8i16 (and store)
+      {2, MVT::v8i16, 3}, // interleave 2 x 8i16 into 16i16 (and store)
 
       {2, MVT::v4i64, 6}, // interleave 2 x 4i64 into 8i64 (and store)
 
       {3, MVT::v2i8, 7},   // interleave 3 x 2i8 into 6i8 (and store)
       {3, MVT::v4i8, 8},   // interleave 3 x 4i8 into 12i8 (and store)
       {3, MVT::v8i8, 11},  // interleave 3 x 8i8 into 24i8 (and store)
       {3, MVT::v16i8, 11}, // interleave 3 x 16i8 into 48i8 (and store)
       {3, MVT::v32i8, 13}, // interleave 3 x 32i8 into 96i8 (and store)

llvm/test/Analysis/CostModel/X86/interleaved-load-i16-stride-2.ll

 ; RUN: opt -loop-vectorize -vectorizer-maximize-bandwidth -S -mattr=+avx2 --debug-only=loop-vectorize < %s 2>&1 | FileCheck %s
 ; REQUIRES: asserts
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 @A = global [1024 x i16] zeroinitializer, align 128
 @B = global [1024 x i8] zeroinitializer, align 128
 
 ; CHECK: LV: Checking a loop in "test"
 ; CHECK: LV: Found an estimated cost of 1 for VF 1 For instruction:   %v0 = load i16, i16* %in0, align 2
 ; CHECK: LV: Found an estimated cost of 3 for VF 2 For instruction:   %v0 = load i16, i16* %in0, align 2
 ; CHECK: LV: Found an estimated cost of 3 for VF 4 For instruction:   %v0 = load i16, i16* %in0, align 2
-; CHECK: LV: Found an estimated cost of 41 for VF 8 For instruction:   %v0 = load i16, i16* %in0, align 2
+; CHECK: LV: Found an estimated cost of 7 for VF 8 For instruction:   %v0 = load i16, i16* %in0, align 2
 ; CHECK: LV: Found an estimated cost of 114 for VF 16 For instruction:   %v0 = load i16, i16* %in0, align 2
 ; CHECK: LV: Found an estimated cost of 228 for VF 32 For instruction:   %v0 = load i16, i16* %in0, align 2
 ; CHECK-NOT: LV: Found an estimated cost of {{[0-9]+}} for VF {{[0-9]+}} For instruction:   %v0 = load i16, i16* %in0, align 2
 
 define void @test() {
 entry:
   br label %for.body
 

llvm/test/Analysis/CostModel/X86/interleaved-store-i16-stride-2.ll

 ; RUN: opt -loop-vectorize -vectorizer-maximize-bandwidth -S -mattr=+avx2 --debug-only=loop-vectorize < %s 2>&1 | FileCheck %s
 ; REQUIRES: asserts
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 @A = global [1024 x i8] zeroinitializer, align 128
 @B = global [1024 x i16] zeroinitializer, align 128
 
 ; CHECK: LV: Checking a loop in "test"
 ; CHECK: LV: Found an estimated cost of 1 for VF 1 For instruction:   store i16 %v1, i16* %out1, align 2
 ; CHECK: LV: Found an estimated cost of 2 for VF 2 For instruction:   store i16 %v1, i16* %out1, align 2
 ; CHECK: LV: Found an estimated cost of 2 for VF 4 For instruction:   store i16 %v1, i16* %out1, align 2
-; CHECK: LV: Found an estimated cost of 49 for VF 8 For instruction:   store i16 %v1, i16* %out1, align 2
+; CHECK: LV: Found an estimated cost of 4 for VF 8 For instruction:   store i16 %v1, i16* %out1, align 2
 ; CHECK: LV: Found an estimated cost of 114 for VF 16 For instruction:   store i16 %v1, i16* %out1, align 2
 ; CHECK: LV: Found an estimated cost of 228 for VF 32 For instruction:   store i16 %v1, i16* %out1, align 2
 ; CHECK-NOT: LV: Found an estimated cost of {{[0-9]+}} for VF {{[0-9]+}} For instruction:   store i16 %v1, i16* %out1, align 2
 
 define void @test() {
 entry:
   br label %for.body