[llvm] 7d52628 - [X86][Costmodel] Load/store i8 Stride=2 VF=2 interleaving costs

[Roman Lebedev via llvm-commits]

Author: Roman Lebedev
Date: 2021-09-29T21:52:44+03:00
New Revision: 7d52628eb0eba6cd27adf7f1b34dc3fb0d9b3a7e

URL: https://github.com/llvm/llvm-project/commit/7d52628eb0eba6cd27adf7f1b34dc3fb0d9b3a7e
DIFF: https://github.com/llvm/llvm-project/commit/7d52628eb0eba6cd27adf7f1b34dc3fb0d9b3a7e.diff

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

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/caKqjr9hb - for intels `Block RThroughput: =2.0`; for ryzens, `Block RThroughput: <=1.0`
So pick cost of `2`.

For store we have:
https://godbolt.org/z/6TTn3eKj8 - for intels `Block RThroughput: =1.0`; for ryzens, `Block RThroughput: <=0.5`
So pick cost of `1`.

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/D110702

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86TargetTransformInfo.cpp
    llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll
    llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 9a040da760c0..f10fffaf89dc 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -5063,6 +5063,8 @@ InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
   // The cost of the loads/stores is accounted for separately.
   //
   static const CostTblEntry AVX2InterleavedLoadTbl[] = {
+      {2, MVT::v2i8, 2},  // (load 4i8 and) deinterleave into 2 x 2i8
+
       {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
@@ -5100,6 +5102,8 @@ InstructionCost X86TTIImpl::getInterleavedMemoryOpCostAVX2(
   };
 
   static const CostTblEntry AVX2InterleavedStoreTbl[] = {
+      {2, MVT::v2i8, 1}, // interleave 2 x 2i8 into 4i8 (and store)
+
       {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)

diff  --git a/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll b/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll
index d817994b9ee1..a3902de92108 100644
--- a/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-load-i8-stride-2.ll
@@ -26,7 +26,7 @@ target triple = "x86_64-unknown-linux-gnu"
 ; AVX1: LV: Found an estimated cost of 166 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 9 for VF 2 For instruction:   %v0 = load i8, i8* %in0, align 1
+; AVX2: LV: Found an estimated cost of 3 for VF 2 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 17 for VF 4 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 33 for VF 8 For instruction:   %v0 = load i8, i8* %in0, align 1
 ; AVX2: LV: Found an estimated cost of 81 for VF 16 For instruction:   %v0 = load i8, i8* %in0, align 1

diff  --git a/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll b/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll
index c04c4aa9f040..81d2ab401e06 100644
--- a/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll
+++ b/llvm/test/Analysis/CostModel/X86/interleaved-store-i8-stride-2.ll
@@ -26,7 +26,7 @@ target triple = "x86_64-unknown-linux-gnu"
 ; AVX1: LV: Found an estimated cost of 166 for VF 32 For instruction:   store i8 %v1, i8* %out1, align 1
 
 ; AVX2: LV: Found an estimated cost of 1 for VF 1 For instruction:   store i8 %v1, i8* %out1, align 1
-; AVX2: LV: Found an estimated cost of 9 for VF 2 For instruction:   store i8 %v1, i8* %out1, align 1
+; AVX2: LV: Found an estimated cost of 2 for VF 2 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 17 for VF 4 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 33 for VF 8 For instruction:   store i8 %v1, i8* %out1, align 1
 ; AVX2: LV: Found an estimated cost of 67 for VF 16 For instruction:   store i8 %v1, i8* %out1, align 1