[PATCH] D110968: [X86][Costmodel] Load/store i8 Stride=4 VF=4 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 store cost is divergent from reality, so fix it.

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/1n4bPh7Tn - 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/r8K9sveqo - 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/D110968

Files:
  llvm/lib/Target/X86/X86TargetTransformInfo.cpp
  llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.ll


Index: llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.ll
===================================================================
--- llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.ll
+++ llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.ll
@@ -27,7 +27,7 @@
 ;
 ; 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 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 5 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
 ; AVX2: LV: Found an estimated cost of 16 for VF 32 For instruction:   store i8 %v3, i8* %out3, align 1
Index: llvm/lib/Target/X86/X86TargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -5145,7 +5145,7 @@
       {3, MVT::v32i8, 13}, // interleave 3 x 32i8 into 96i8 (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::v4i8, 4},   // 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)
       {4, MVT::v32i8, 12}, // interleave 4 x 32i8 into 128i8 (and store)


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