[llvm] 201877d - [CostModel][X86] Improve accuracy of vXi8 multiply reduction costs
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Tue Apr 6 03:53:33 PDT 2021
Author: Simon Pilgrim
Date: 2021-04-06T11:53:22+01:00
New Revision: 201877d57264543d8ac5ca48f15bc0bc7c80b8ce
URL: https://github.com/llvm/llvm-project/commit/201877d57264543d8ac5ca48f15bc0bc7c80b8ce
DIFF: https://github.com/llvm/llvm-project/commit/201877d57264543d8ac5ca48f15bc0bc7c80b8ce.diff
LOG: [CostModel][X86] Improve accuracy of vXi8 multiply reduction costs
After rG47321c311bdbe0145b9bf45d822185c37b19fa50 we promote vXi8 reductions to vXi16 to create a much faster PMULLW mul reduction, followed by a (free) truncation. This avoids the high cost of repeated vXi8 multiplications (which extend+multiply+truncate to/from vXi16 types....).
Fixes the missing vXi8 mul reduction vectorization in PR42674 (Comment #20) 'mul16' test case.
Added:
Modified:
llvm/lib/Target/X86/X86TargetTransformInfo.cpp
llvm/test/Analysis/CostModel/X86/reduce-mul.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 5f67ddcee489e..a7479330a9a9f 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -3408,6 +3408,16 @@ int X86TTIImpl::getArithmeticReductionCost(unsigned Opcode, VectorType *ValTy,
auto *ValVTy = cast<FixedVectorType>(ValTy);
+ // Special case: vXi8 mul reductions are performed as vXi16.
+ if (ISD == ISD::MUL && MTy.getScalarType() == MVT::i8) {
+ auto *WideSclTy = IntegerType::get(ValVTy->getContext(), 16);
+ auto *WideVecTy = FixedVectorType::get(WideSclTy, ValVTy->getNumElements());
+ return getCastInstrCost(Instruction::ZExt, WideVecTy, ValTy,
+ TargetTransformInfo::CastContextHint::None,
+ CostKind) +
+ getArithmeticReductionCost(Opcode, WideVecTy, IsPairwise, CostKind);
+ }
+
unsigned ArithmeticCost = 0;
if (LT.first != 1 && MTy.isVector() &&
MTy.getVectorNumElements() < ValVTy->getNumElements()) {
diff --git a/llvm/test/Analysis/CostModel/X86/reduce-mul.ll b/llvm/test/Analysis/CostModel/X86/reduce-mul.ll
index eca510f511bde..e51d89ac0e5f2 100644
--- a/llvm/test/Analysis/CostModel/X86/reduce-mul.ll
+++ b/llvm/test/Analysis/CostModel/X86/reduce-mul.ll
@@ -187,64 +187,84 @@ define i32 @reduce_i16(i32 %arg) {
}
define i32 @reduce_i8(i32 %arg) {
-; SSE-LABEL: 'reduce_i8'
-; SSE-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
-; SSE-NEXT: Cost Model: Found an estimated cost of 27 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
-; SSE-NEXT: Cost Model: Found an estimated cost of 40 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
-; SSE-NEXT: Cost Model: Found an estimated cost of 53 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
-; SSE-NEXT: Cost Model: Found an estimated cost of 65 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
-; SSE-NEXT: Cost Model: Found an estimated cost of 89 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
-; SSE-NEXT: Cost Model: Found an estimated cost of 137 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
-; SSE-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
+; SSE2-LABEL: 'reduce_i8'
+; SSE2-NEXT: Cost Model: Found an estimated cost of 4 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
+; SSE2-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
+; SSE2-NEXT: Cost Model: Found an estimated cost of 8 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
+; SSE2-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
+; SSE2-NEXT: Cost Model: Found an estimated cost of 16 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
+; SSE2-NEXT: Cost Model: Found an estimated cost of 26 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
+; SSE2-NEXT: Cost Model: Found an estimated cost of 46 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
+; SSE2-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
+;
+; SSSE3-LABEL: 'reduce_i8'
+; SSSE3-NEXT: Cost Model: Found an estimated cost of 4 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
+; SSSE3-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
+; SSSE3-NEXT: Cost Model: Found an estimated cost of 8 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
+; SSSE3-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
+; SSSE3-NEXT: Cost Model: Found an estimated cost of 16 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
+; SSSE3-NEXT: Cost Model: Found an estimated cost of 26 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
+; SSSE3-NEXT: Cost Model: Found an estimated cost of 46 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
+; SSSE3-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
+;
+; SSE42-LABEL: 'reduce_i8'
+; SSE42-NEXT: Cost Model: Found an estimated cost of 4 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
+; SSE42-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
+; SSE42-NEXT: Cost Model: Found an estimated cost of 8 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
+; SSE42-NEXT: Cost Model: Found an estimated cost of 10 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
+; SSE42-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
+; SSE42-NEXT: Cost Model: Found an estimated cost of 22 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
+; SSE42-NEXT: Cost Model: Found an estimated cost of 38 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
+; SSE42-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
;
; AVX1-LABEL: 'reduce_i8'
-; AVX1-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
-; AVX1-NEXT: Cost Model: Found an estimated cost of 27 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
-; AVX1-NEXT: Cost Model: Found an estimated cost of 40 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
-; AVX1-NEXT: Cost Model: Found an estimated cost of 53 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
-; AVX1-NEXT: Cost Model: Found an estimated cost of 66 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
-; AVX1-NEXT: Cost Model: Found an estimated cost of 92 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
-; AVX1-NEXT: Cost Model: Found an estimated cost of 144 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
+; AVX1-NEXT: Cost Model: Found an estimated cost of 4 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
+; AVX1-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
+; AVX1-NEXT: Cost Model: Found an estimated cost of 8 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
+; AVX1-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
+; AVX1-NEXT: Cost Model: Found an estimated cost of 22 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
+; AVX1-NEXT: Cost Model: Found an estimated cost of 39 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
+; AVX1-NEXT: Cost Model: Found an estimated cost of 73 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
; AVX1-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
;
; AVX2-LABEL: 'reduce_i8'
-; AVX2-NEXT: Cost Model: Found an estimated cost of 9 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
-; AVX2-NEXT: Cost Model: Found an estimated cost of 17 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
-; AVX2-NEXT: Cost Model: Found an estimated cost of 25 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
-; AVX2-NEXT: Cost Model: Found an estimated cost of 33 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
-; AVX2-NEXT: Cost Model: Found an estimated cost of 41 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
-; AVX2-NEXT: Cost Model: Found an estimated cost of 58 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
-; AVX2-NEXT: Cost Model: Found an estimated cost of 92 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
+; AVX2-NEXT: Cost Model: Found an estimated cost of 4 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
+; AVX2-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
+; AVX2-NEXT: Cost Model: Found an estimated cost of 8 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
+; AVX2-NEXT: Cost Model: Found an estimated cost of 10 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
+; AVX2-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
+; AVX2-NEXT: Cost Model: Found an estimated cost of 18 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
+; AVX2-NEXT: Cost Model: Found an estimated cost of 28 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
; AVX2-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
;
; AVX512F-LABEL: 'reduce_i8'
-; AVX512F-NEXT: Cost Model: Found an estimated cost of 7 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
-; AVX512F-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
-; AVX512F-NEXT: Cost Model: Found an estimated cost of 19 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
-; AVX512F-NEXT: Cost Model: Found an estimated cost of 25 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
-; AVX512F-NEXT: Cost Model: Found an estimated cost of 31 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
-; AVX512F-NEXT: Cost Model: Found an estimated cost of 45 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
-; AVX512F-NEXT: Cost Model: Found an estimated cost of 71 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
+; AVX512F-NEXT: Cost Model: Found an estimated cost of 4 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
+; AVX512F-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
+; AVX512F-NEXT: Cost Model: Found an estimated cost of 8 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
+; AVX512F-NEXT: Cost Model: Found an estimated cost of 10 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
+; AVX512F-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
+; AVX512F-NEXT: Cost Model: Found an estimated cost of 20 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
+; AVX512F-NEXT: Cost Model: Found an estimated cost of 31 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
; AVX512F-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
;
; AVX512BW-LABEL: 'reduce_i8'
-; AVX512BW-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
-; AVX512BW-NEXT: Cost Model: Found an estimated cost of 11 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
-; AVX512BW-NEXT: Cost Model: Found an estimated cost of 16 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
-; AVX512BW-NEXT: Cost Model: Found an estimated cost of 21 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
-; AVX512BW-NEXT: Cost Model: Found an estimated cost of 26 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
-; AVX512BW-NEXT: Cost Model: Found an estimated cost of 31 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
-; AVX512BW-NEXT: Cost Model: Found an estimated cost of 42 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
+; AVX512BW-NEXT: Cost Model: Found an estimated cost of 4 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
+; AVX512BW-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
+; AVX512BW-NEXT: Cost Model: Found an estimated cost of 8 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
+; AVX512BW-NEXT: Cost Model: Found an estimated cost of 10 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
+; AVX512BW-NEXT: Cost Model: Found an estimated cost of 12 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
+; AVX512BW-NEXT: Cost Model: Found an estimated cost of 15 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
+; AVX512BW-NEXT: Cost Model: Found an estimated cost of 20 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
; AVX512BW-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
;
; AVX512DQ-LABEL: 'reduce_i8'
-; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 7 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
-; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 13 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
-; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 19 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
-; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 25 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
-; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 31 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
-; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 45 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
-; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 71 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
+; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 4 for instruction: %V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
+; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 6 for instruction: %V4 = call i8 @llvm.vector.reduce.mul.v4i8(<4 x i8> undef)
+; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 8 for instruction: %V8 = call i8 @llvm.vector.reduce.mul.v8i8(<8 x i8> undef)
+; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 10 for instruction: %V16 = call i8 @llvm.vector.reduce.mul.v16i8(<16 x i8> undef)
+; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 14 for instruction: %V32 = call i8 @llvm.vector.reduce.mul.v32i8(<32 x i8> undef)
+; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 20 for instruction: %V64 = call i8 @llvm.vector.reduce.mul.v64i8(<64 x i8> undef)
+; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 31 for instruction: %V128 = call i8 @llvm.vector.reduce.mul.v128i8(<128 x i8> undef)
; AVX512DQ-NEXT: Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
;
%V2 = call i8 @llvm.vector.reduce.mul.v2i8(<2 x i8> undef)
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