[AArch64] Add extra reverse costs.

[dmgreen]

Summary

This adds some extra costs for reverse shuffles under AArch64, filling in the i16/f16/i8 gaps in the cost model.

[samtebbs]

LGTM

Out of interest, do you have any benchmark results to show how these new costs improves things?

[dmgreen]

In D124786#3488503, @samtebbs wrote:

LGTM

Out of interest, do you have any benchmark results to show how these new costs improves things?

Thanks. I only noticed this from an issue in the cost of a reversed interleaving group from D124612. It stopped that patch making things worse.

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

static const CostTblEntry ShuffleTbl[] = {
       { TTI::SK_PermuteSingleSrc, MVT::v16i8, 8 }, // constpool + load + tbl
       // Reverse can be lowered with `rev`.
       { TTI::SK_Reverse, MVT::v2i32, 1 }, // mov.
       { TTI::SK_Reverse, MVT::v4i32, 2 }, // REV64; EXT
       { TTI::SK_Reverse, MVT::v2i64, 1 }, // mov.
       { TTI::SK_Reverse, MVT::v2f32, 1 }, // mov.
       { TTI::SK_Reverse, MVT::v4f32, 2 }, // REV64; EXT
       { TTI::SK_Reverse, MVT::v2f64, 1 }, // mov.
+      { TTI::SK_Reverse, MVT::v8f16, 2 }, // REV64; EXT
+      { TTI::SK_Reverse, MVT::v8i16, 2 }, // REV64; EXT
+      { TTI::SK_Reverse, MVT::v16i8, 2 }, // REV64; EXT
+      { TTI::SK_Reverse, MVT::v4f16, 1 }, // REV64
+      { TTI::SK_Reverse, MVT::v4i16, 1 }, // REV64
+      { TTI::SK_Reverse, MVT::v8i8, 1 }, // REV64
       // Broadcast shuffle kinds for scalable vectors
       { TTI::SK_Broadcast, MVT::nxv16i8,  1 },
       { TTI::SK_Broadcast, MVT::nxv8i16,  1 },
       { TTI::SK_Broadcast, MVT::nxv4i32,  1 },
       { TTI::SK_Broadcast, MVT::nxv2i64,  1 },
       { TTI::SK_Broadcast, MVT::nxv2f16,  1 },
       { TTI::SK_Broadcast, MVT::nxv4f16,  1 },
       { TTI::SK_Broadcast, MVT::nxv8f16,  1 },

llvm/test/Analysis/CostModel/AArch64/getIntrinsicInstrCost-vector-reverse.ll

 ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
 ; Check getIntrinsicInstrCost in BasicTTIImpl.h for vector.reverse
 
 ; RUN: opt -passes='print<cost-model>' 2>&1 -disable-output -mtriple=aarch64--linux-gnu -mattr=+sve  < %s | FileCheck %s
 
 define void @vector_reverse() #0{
 ; CHECK-LABEL: 'vector_reverse'
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 90 for instruction: %1 = call <16 x i8> @llvm.experimental.vector.reverse.v16i8(<16 x i8> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 180 for instruction: %2 = call <32 x i8> @llvm.experimental.vector.reverse.v32i8(<32 x i8> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 42 for instruction: %3 = call <8 x i16> @llvm.experimental.vector.reverse.v8i16(<8 x i16> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 84 for instruction: %4 = call <16 x i16> @llvm.experimental.vector.reverse.v16i16(<16 x i16> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = call <16 x i8> @llvm.experimental.vector.reverse.v16i8(<16 x i8> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %2 = call <32 x i8> @llvm.experimental.vector.reverse.v32i8(<32 x i8> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %3 = call <8 x i16> @llvm.experimental.vector.reverse.v8i16(<8 x i16> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %4 = call <16 x i16> @llvm.experimental.vector.reverse.v16i16(<16 x i16> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %5 = call <4 x i32> @llvm.experimental.vector.reverse.v4i32(<4 x i32> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %6 = call <8 x i32> @llvm.experimental.vector.reverse.v8i32(<8 x i32> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %7 = call <2 x i64> @llvm.experimental.vector.reverse.v2i64(<2 x i64> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %8 = call <4 x i64> @llvm.experimental.vector.reverse.v4i64(<4 x i64> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 42 for instruction: %9 = call <8 x half> @llvm.experimental.vector.reverse.v8f16(<8 x half> undef)
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 84 for instruction: %10 = call <16 x half> @llvm.experimental.vector.reverse.v16f16(<16 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %9 = call <8 x half> @llvm.experimental.vector.reverse.v8f16(<8 x half> undef)
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %10 = call <16 x half> @llvm.experimental.vector.reverse.v16f16(<16 x half> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %11 = call <4 x float> @llvm.experimental.vector.reverse.v4f32(<4 x float> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %12 = call <8 x float> @llvm.experimental.vector.reverse.v8f32(<8 x float> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %13 = call <2 x double> @llvm.experimental.vector.reverse.v2f64(<2 x double> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %14 = call <4 x double> @llvm.experimental.vector.reverse.v4f64(<4 x double> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 42 for instruction: %15 = call <8 x bfloat> @llvm.experimental.vector.reverse.v8bf16(<8 x bfloat> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 84 for instruction: %16 = call <16 x bfloat> @llvm.experimental.vector.reverse.v16bf16(<16 x bfloat> undef)
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;

llvm/test/Analysis/CostModel/AArch64/shuffle-reverse.ll

 ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
 ; RUN: opt < %s -mtriple=aarch64--linux-gnu -passes='print<cost-model>' 2>&1 -disable-output | FileCheck %s
 
 ;
 ; Verify the cost model for reverse shuffles.
 ;
 
 ;; Reverse shuffles should be lowered to vrev and possibly a vext (for quadwords, on neon)
 define void @reverse() {
 ; CHECK-LABEL: 'reverse'
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v2i8 = shufflevector <2 x i8> undef, <2 x i8> undef, <2 x i32> <i32 1, i32 0>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 18 for instruction: %v4i8 = shufflevector <4 x i8> undef, <4 x i8> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 42 for instruction: %v8i8 = shufflevector <8 x i8> undef, <8 x i8> undef, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 90 for instruction: %v16i8 = shufflevector <16 x i8> undef, <16 x i8> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 12, i32 11, i32 10, i32 9, i32 8, i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v4i8 = shufflevector <4 x i8> undef, <4 x i8> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v8i8 = shufflevector <8 x i8> undef, <8 x i8> undef, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v16i8 = shufflevector <16 x i8> undef, <16 x i8> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 12, i32 11, i32 10, i32 9, i32 8, i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v2i16 = shufflevector <2 x i16> undef, <2 x i16> undef, <2 x i32> <i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v4i16 = shufflevector <4 x i16> undef, <4 x i16> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 42 for instruction: %v8i16 = shufflevector <8 x i16> undef, <8 x i16> undef, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 84 for instruction: %v16i16 = shufflevector <16 x i16> undef, <16 x i16> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 12, i32 11, i32 10, i32 9, i32 8, i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v8i16 = shufflevector <8 x i16> undef, <8 x i16> undef, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %v16i16 = shufflevector <16 x i16> undef, <16 x i16> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 12, i32 11, i32 10, i32 9, i32 8, i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v2i32 = shufflevector <2 x i32> undef, <2 x i32> undef, <2 x i32> <i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v4i32 = shufflevector <4 x i32> undef, <4 x i32> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %v8i32 = shufflevector <8 x i32> undef, <8 x i32> undef, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v2i64 = shufflevector <2 x i64> undef, <2 x i64> undef, <2 x i32> <i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v4i64 = shufflevector <4 x i64> undef, <4 x i64> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %v2f16 = shufflevector <2 x half> undef, <2 x half> undef, <2 x i32> <i32 1, i32 0>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v2f16 = shufflevector <2 x half> undef, <2 x half> undef, <2 x i32> <i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v4f16 = shufflevector <4 x half> undef, <4 x half> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 42 for instruction: %v8f16 = shufflevector <8 x half> undef, <8 x half> undef, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 84 for instruction: %v16f16 = shufflevector <16 x half> undef, <16 x half> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 12, i32 11, i32 10, i32 9, i32 8, i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v8f16 = shufflevector <8 x half> undef, <8 x half> undef, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %v16f16 = shufflevector <16 x half> undef, <16 x half> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 12, i32 11, i32 10, i32 9, i32 8, i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v2f32 = shufflevector <2 x float> undef, <2 x float> undef, <2 x i32> <i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v4f32 = shufflevector <4 x float> undef, <4 x float> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %v8f32 = shufflevector <8 x float> undef, <8 x float> undef, <8 x i32> <i32 7, i32 6, i32 5, i32 4, i32 3, i32 2, i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v2f64 = shufflevector <2 x double> undef, <2 x double> undef, <2 x i32> <i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v4f64 = shufflevector <4 x double> undef, <4 x double> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
   %v2i8 = shufflevector <2 x i8> undef, <2 x i8> undef, <2 x i32> <i32 1, i32 0>