[PATCH] D110956: [X86][Costmodel] Load/store i8 Stride=3 VF=2 interleaving costs

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri created this revision.
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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/WYscYMcW4 - for intels `Block RThroughput: =3.0`; for ryzens, `Block RThroughput: <=1.5`
So pick cost of `3`.

For store we have:
https://godbolt.org/z/e9qvYdbbs - 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.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D110956

Files:
  llvm/lib/Target/X86/X86TargetTransformInfo.cpp
  llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-3.ll
  llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-3.ll


Index: llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-3.ll
===================================================================
--- llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-3.ll
+++ llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-3.ll
@@ -26,7 +26,7 @@
 ; AVX1: LV: Found an estimated cost of 249 for VF 32 For instruction:   store i8 %v2, i8* %out2, align 1
 ;
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   store i8 %v2, i8* %out2, align 1
-; AVX2: LV: Found an estimated cost of 10 for VF 2 For instruction:   store i8 %v2, i8* %out2, align 1
+; AVX2: LV: Found an estimated cost of 7 for VF 2 For instruction:   store i8 %v2, i8* %out2, align 1
 ; AVX2: LV: Found an estimated cost of 11 for VF 4 For instruction:   store i8 %v2, i8* %out2, align 1
 ; AVX2: LV: Found an estimated cost of 14 for VF 8 For instruction:   store i8 %v2, i8* %out2, align 1
 ; AVX2: LV: Found an estimated cost of 13 for VF 16 For instruction:   store i8 %v2, i8* %out2, align 1
Index: llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-3.ll
===================================================================
--- llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-3.ll
+++ llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-3.ll
@@ -26,7 +26,7 @@
 ; AVX1: LV: Found an estimated cost of 249 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 6 for VF 2 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 7 for VF 4 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 12 for VF 8 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 13 for VF 16 For instruction:   %v0 = load i8, i8* %in0, align 1
Index: llvm/lib/Target/X86/X86TargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -5086,7 +5086,7 @@
       {2, MVT::v8i64, 8}, // (load 16i64 and) deinterleave into 2 x 8i64
       {2, MVT::v16i64, 16}, // (load 32i64 and) deinterleave into 2 x 16i64
 
-      {3, MVT::v2i8, 10},  // (load 6i8 and) deinterleave into 3 x 2i8
+      {3, MVT::v2i8, 3},  // (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
@@ -5138,7 +5138,7 @@
       {2, MVT::v8i64, 8}, // interleave 2 x 8i64 into 16i64 (and store)
       {2, MVT::v16i64, 16}, // interleave 2 x 16i64 into 32i64 (and store)
 
-      {3, MVT::v2i8, 7},   // interleave 3 x 2i8 into 6i8 (and store)
+      {3, MVT::v2i8, 4},   // 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)


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