[llvm] 57492b1 - [RISCV] Cost model for general case of dual vector permute
Philip Reames via llvm-commits
llvm-commits at lists.llvm.org
Wed Mar 29 07:37:07 PDT 2023
Author: Philip Reames
Date: 2023-03-29T07:36:35-07:00
New Revision: 57492b1eeb99761afbe97a893df19b934c11e6f1
URL: https://github.com/llvm/llvm-project/commit/57492b1eeb99761afbe97a893df19b934c11e6f1
DIFF: https://github.com/llvm/llvm-project/commit/57492b1eeb99761afbe97a893df19b934c11e6f1.diff
LOG: [RISCV] Cost model for general case of dual vector permute
The cost model was not accounting for the fact that we can generate a dual vrgather + an index expression sequence instead of scalarizing.
A couple cases to call out:
1) I did not model the difference between vrgather and vrgatherei16. The result is the constant pool cost can be slightly understated on RV32. I don't think we care, but if someone disagrees, this would be easy to add.
2) Our current codegen for i8 vectors longer than 256 (which is the limit of what this costs) has some room for improvement.
3) As indicated by the *regression* in reported cost for <2 x iN> vectors, our current vector lowering is missing support for a sub-case where scalarize-and-insert is actually faster than the generic fallback path.
Differential Revision: https://reviews.llvm.org/D147063
Added:
Modified:
llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
llvm/test/Analysis/CostModel/RISCV/shuffle-permute.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
index 20379b1f22b78..72f2d67369d89 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
@@ -302,6 +302,26 @@ InstructionCost RISCVTTIImpl::getShuffleCost(TTI::ShuffleKind Kind,
return IndexCost + getLMULCost(LT.second);
}
}
+ break;
+ }
+ case TTI::SK_PermuteTwoSrc: {
+ if (Mask.size() >= 2 && LT.second.isFixedLengthVector()) {
+ // 2 x (vrgather + cost of generating the mask constant) + cost of mask
+ // register for the second vrgather. We model this for an unknown
+ // (shuffle) mask.
+ if (LT.first == 1 &&
+ (LT.second.getScalarSizeInBits() != 8 ||
+ LT.second.getVectorNumElements() <= 256)) {
+ auto &C = Tp->getContext();
+ auto EC = Tp->getElementCount();
+ VectorType *IdxTy = VectorType::get(IntegerType::getInt8Ty(C), EC);
+ VectorType *MaskTy = VectorType::get(IntegerType::getInt1Ty(C), EC);
+ InstructionCost IndexCost = getConstantPoolLoadCost(IdxTy, CostKind);
+ InstructionCost MaskCost = getConstantPoolLoadCost(MaskTy, CostKind);
+ return 2 * IndexCost + 2 * getLMULCost(LT.second) + MaskCost;
+ }
+ }
+ break;
}
}
};
diff --git a/llvm/test/Analysis/CostModel/RISCV/shuffle-permute.ll b/llvm/test/Analysis/CostModel/RISCV/shuffle-permute.ll
index 9e2706baaf667..67a5b43338899 100644
--- a/llvm/test/Analysis/CostModel/RISCV/shuffle-permute.ll
+++ b/llvm/test/Analysis/CostModel/RISCV/shuffle-permute.ll
@@ -52,34 +52,34 @@ define void @general_permute_single_source() {
define void @general_permute_two_source() {
;
; CHECK-LABEL: 'general_permute_two_source'
-; 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 3, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %v4i8 = shufflevector <4 x i8> undef, <4 x i8> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 30 for instruction: %v8i8 = shufflevector <8 x i8> undef, <8 x i8> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 62 for instruction: %v16i8 = shufflevector <16 x i8> undef, <16 x i8> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 3, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %v4i16 = shufflevector <4 x i16> undef, <4 x i16> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 30 for instruction: %v8i16 = shufflevector <8 x i16> undef, <8 x i16> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 62 for instruction: %v16i16 = shufflevector <16 x i16> undef, <16 x i16> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 3, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %v4i32 = shufflevector <4 x i32> undef, <4 x i32> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 30 for instruction: %v8i32 = shufflevector <8 x i32> undef, <8 x i32> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 62 for instruction: %v16i32 = shufflevector <16 x i32> undef, <16 x i32> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 16 for instruction: %v2i64 = shufflevector <2 x i64> undef, <2 x i64> undef, <2 x i32> <i32 3, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 34 for instruction: %v4i64 = shufflevector <4 x i64> undef, <4 x i64> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 70 for instruction: %v8i64 = shufflevector <8 x i64> undef, <8 x i64> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 142 for instruction: %v16i64 = shufflevector <16 x i64> undef, <16 x i64> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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: %v2half = shufflevector <2 x half> undef, <2 x half> undef, <2 x i32> <i32 3, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %v4half = shufflevector <4 x half> undef, <4 x half> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 30 for instruction: %v8half = shufflevector <8 x half> undef, <8 x half> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 62 for instruction: %v16half = shufflevector <16 x half> undef, <16 x half> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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: %v2float = shufflevector <2 x float> undef, <2 x float> undef, <2 x i32> <i32 3, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %v4float = shufflevector <4 x float> undef, <4 x float> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 30 for instruction: %v8float = shufflevector <8 x float> undef, <8 x float> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 62 for instruction: %v16float = shufflevector <16 x float> undef, <16 x float> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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: %v2double = shufflevector <2 x double> undef, <2 x double> undef, <2 x i32> <i32 3, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %v4double = shufflevector <4 x double> undef, <4 x double> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 30 for instruction: %v8double = shufflevector <8 x double> undef, <8 x double> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
-; CHECK-NEXT: Cost Model: Found an estimated cost of 62 for instruction: %v16double = shufflevector <16 x double> undef, <16 x double> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 11 for instruction: %v2i8 = shufflevector <2 x i8> undef, <2 x i8> undef, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v4i8 = shufflevector <4 x i8> undef, <4 x i8> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v8i8 = shufflevector <8 x i8> undef, <8 x i8> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v16i8 = shufflevector <16 x i8> undef, <16 x i8> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 11 for instruction: %v2i16 = shufflevector <2 x i16> undef, <2 x i16> undef, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v4i16 = shufflevector <4 x i16> undef, <4 x i16> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v8i16 = shufflevector <8 x i16> undef, <8 x i16> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %v16i16 = shufflevector <16 x i16> undef, <16 x i16> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 11 for instruction: %v2i32 = shufflevector <2 x i32> undef, <2 x i32> undef, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v4i32 = shufflevector <4 x i32> undef, <4 x i32> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %v8i32 = shufflevector <8 x i32> undef, <8 x i32> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 17 for instruction: %v16i32 = shufflevector <16 x i32> undef, <16 x i32> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 11 for instruction: %v2i64 = shufflevector <2 x i64> undef, <2 x i64> undef, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %v4i64 = shufflevector <4 x i64> undef, <4 x i64> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 17 for instruction: %v8i64 = shufflevector <8 x i64> undef, <8 x i64> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 25 for instruction: %v16i64 = shufflevector <16 x i64> undef, <16 x i64> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 11 for instruction: %v2half = shufflevector <2 x half> undef, <2 x half> undef, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v4half = shufflevector <4 x half> undef, <4 x half> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v8half = shufflevector <8 x half> undef, <8 x half> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %v16half = shufflevector <16 x half> undef, <16 x half> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 11 for instruction: %v2float = shufflevector <2 x float> undef, <2 x float> undef, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %v4float = shufflevector <4 x float> undef, <4 x float> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %v8float = shufflevector <8 x float> undef, <8 x float> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 17 for instruction: %v16float = shufflevector <16 x float> undef, <16 x float> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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 11 for instruction: %v2double = shufflevector <2 x double> undef, <2 x double> undef, <2 x i32> <i32 3, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %v4double = shufflevector <4 x double> undef, <4 x double> undef, <4 x i32> <i32 5, i32 7, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 17 for instruction: %v8double = shufflevector <8 x double> undef, <8 x double> undef, <8 x i32> <i32 14, i32 6, i32 5, i32 4, i32 13, i32 2, i32 1, i32 0>
+; CHECK-NEXT: Cost Model: Found an estimated cost of 25 for instruction: %v16double = shufflevector <16 x double> undef, <16 x double> undef, <16 x i32> <i32 15, i32 14, i32 13, i32 17, i32 11, i32 20, 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: ret void
;
%v2i8 = shufflevector <2 x i8> undef, <2 x i8> undef, <2 x i32> <i32 3, i32 0>
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