[llvm] 74e4a0e - [X86][Costmodel] Load/store i8 Stride=4 VF=8 interleaving costs

[Roman Lebedev via llvm-commits]

Author: Roman Lebedev
Date: 2021-10-02T13:40:20+03:00
New Revision: 74e4a0e327579bfc3b00f6af0c9fd408c5843e8b

URL: https://github.com/llvm/llvm-project/commit/74e4a0e327579bfc3b00f6af0c9fd408c5843e8b
DIFF: https://github.com/llvm/llvm-project/commit/74e4a0e327579bfc3b00f6af0c9fd408c5843e8b.diff

LOG: [X86][Costmodel] Load/store i8 Stride=4 VF=8 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/v7746Wcf7 - for intels `Block RThroughput: =12.0`; for ryzens, `Block RThroughput: <=6.0`
So pick cost of `12`.

For store we have:
https://godbolt.org/z/aEeEohEbP - 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/D110969

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 6e3aaba56222..588b42b7b454 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -5096,7 +5096,7 @@ InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
 
       {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::v8i8, 12},  // (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
 
@@ -5146,7 +5146,7 @@ InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
 
       {4, MVT::v2i8, 4},  // interleave 4 x 2i8 into 8i8 (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::v8i8, 4},  // 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)
 

diff  --git a/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-4.ll b/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-4.ll
index a89458f266b8..2ef0fc3e3bfe 100644
--- a/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-4.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-4.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 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 13 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
 ; AVX2: LV: Found an estimated cost of 84 for VF 32 For instruction:   %v0 = load i8, i8* %in0, align 1
 ;

diff  --git a/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.ll b/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.ll
index 5b2e7fae6cf5..962beeb3dbec 100644
--- a/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-4.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 %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 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 5 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
 ;