[PATCH] D145973: [RISCV] Improve SK_Reverse shuffle costs for fixed length vectors
Philip Reames via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 13 11:36:56 PDT 2023
reames created this revision.
reames added reviewers: l.frisken, craig.topper, asb.
Herald added subscribers: jobnoorman, VincentWu, vkmr, frasercrmck, evandro, luismarques, apazos, sameer.abuasal, s.egerton, Jim, benna, psnobl, jocewei, PkmX, the_o, brucehoult, MartinMosbeck, rogfer01, edward-jones, zzheng, jrtc27, shiva0217, kito-cheng, niosHD, sabuasal, bollu, simoncook, johnrusso, rbar, hiraditya, arichardson, mcrosier.
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As noted by @luke (https://reviews.llvm.org/D145953#inline-1409312), we were accounting for the cost of vector element size using vlenb whereas the expression can be constant folded for fixed length vectors.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D145973
Files:
llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
llvm/test/Analysis/CostModel/RISCV/shuffle-reverse.ll
Index: llvm/test/Analysis/CostModel/RISCV/shuffle-reverse.ll
===================================================================
--- llvm/test/Analysis/CostModel/RISCV/shuffle-reverse.ll
+++ llvm/test/Analysis/CostModel/RISCV/shuffle-reverse.ll
@@ -8,28 +8,28 @@
define void @reverse() {
;
; CHECK-LABEL: 'reverse'
-; CHECK-NEXT: Cost Model: Found an estimated cost of 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 6 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 3 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 1 for instruction: ret void
;
%v2i8 = shufflevector <2 x i8> undef, <2 x i8> undef, <2 x i32> <i32 1, i32 0>
Index: llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
+++ llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
@@ -333,7 +333,12 @@
// TODO: Multiplying by LT.first implies this legalizes into multiple copies
// of similar code, but I think we expand through memory.
return 2 * LT.first * getLMULCost(LT.second);
- case TTI::SK_Reverse:
+ case TTI::SK_Reverse: {
+ // TODO: Cases to improve here:
+ // * LMUL > 1
+ // * i64 on RV32
+ // * i1 vector\
+
// Most of the cost here is producing the vrgather index register
// Example sequence:
// csrr a0, vlenb
@@ -343,10 +348,15 @@
// vid.v v9
// vrsub.vx v10, v9, a0
// vrgather.vv v9, v8, v10
+ unsigned LenCost = 3;
+ if (LT.second.isFixedLengthVector())
+ // vrsub.vi has a 5 bit immediate field, otherwise an li suffices
+ LenCost = isInt<5>(LT.second.getVectorNumElements() - 1) ? 0 : 1;
if (Tp->getElementType()->isIntegerTy(1))
// Mask operation additionally required extend and truncate
- return LT.first * 9;
- return LT.first * 6;
+ return LT.first * (LenCost + 6);
+ return LT.first * (LenCost + 3);
+ }
}
return BaseT::getShuffleCost(Kind, Tp, Mask, CostKind, Index, SubTp);
}
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