[llvm] 7ba7026 - [SLP][AArch64] Implement lookahead operand reordering score of splat loads for AArch64

Vasileios Porpodas via llvm-commits llvm-commits at lists.llvm.org
Fri Apr 22 07:48:07 PDT 2022


Author: Vasileios Porpodas
Date: 2022-04-22T07:29:58-07:00
New Revision: 7ba702644bac6df166a02bbd692c1599a95a7c8b

URL: https://github.com/llvm/llvm-project/commit/7ba702644bac6df166a02bbd692c1599a95a7c8b
DIFF: https://github.com/llvm/llvm-project/commit/7ba702644bac6df166a02bbd692c1599a95a7c8b.diff

LOG: [SLP][AArch64] Implement lookahead operand reordering score of splat loads for AArch64

The original patch (https://reviews.llvm.org/D121354) targets x86 and adjusts
the lookahead score of splat loads ad they can be done by the `movddup`
instruction that combines the load and the broadcast and is cheap to execute.

A similar issue shows up on AArch64. The `ld1r` instruction performs a broadcast
load and is cheap to execute.

This patch implements the TargetTransformInfo hooks for AArch64.

Differential Revision: https://reviews.llvm.org/D123638

Added: 
    

Modified: 
    llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
    llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
    llvm/test/Transforms/SLPVectorizer/AArch64/splat-loads.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index e14849b7f5da1..303bff3bc0e3b 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -2600,6 +2600,17 @@ InstructionCost AArch64TTIImpl::getShuffleCost(TTI::ShuffleKind Kind,
   if (Kind == TTI::SK_Broadcast || Kind == TTI::SK_Transpose ||
       Kind == TTI::SK_Select || Kind == TTI::SK_PermuteSingleSrc ||
       Kind == TTI::SK_Reverse) {
+
+    // Check for broadcast loads.
+    if (Kind == TTI::SK_Broadcast) {
+      bool IsLoad = !Args.empty() && llvm::all_of(Args, [](const Value *V) {
+        return isa<LoadInst>(V);
+      });
+      if (IsLoad && isLegalBroadcastLoad(Tp->getElementType(),
+                                         LT.second.getVectorElementCount()))
+        return 0; // broadcast is handled by ld1r
+    }
+
     static const CostTblEntry ShuffleTbl[] = {
       // Broadcast shuffle kinds can be performed with 'dup'.
       { TTI::SK_Broadcast, MVT::v8i8,  1 },

diff  --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
index 92005b3ba40c9..c68676d021960 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
@@ -278,6 +278,23 @@ class AArch64TTIImpl : public BasicTTIImplBase<AArch64TTIImpl> {
     return isLegalMaskedGatherScatter(DataType);
   }
 
+  bool isLegalBroadcastLoad(Type *ElementTy, ElementCount NumElements) const {
+    // Return true if we can generate a `ld1r` splat load instruction.
+    if (!ST->hasNEON() || NumElements.isScalable())
+      return false;
+    switch (unsigned ElementBits = ElementTy->getScalarSizeInBits()) {
+    case 8:
+    case 16:
+    case 32:
+    case 64: {
+      // We accept bit-widths >= 64bits and elements {8,16,32,64} bits.
+      unsigned VectorBits = NumElements.getFixedValue() * ElementBits;
+      return VectorBits >= 64;
+    }
+    }
+    return false;
+  }
+
   bool isLegalNTStore(Type *DataType, Align Alignment) {
     // NOTE: The logic below is mostly geared towards LV, which calls it with
     //       vectors with 2 elements. We might want to improve that, if other

diff  --git a/llvm/test/Transforms/SLPVectorizer/AArch64/splat-loads.ll b/llvm/test/Transforms/SLPVectorizer/AArch64/splat-loads.ll
index 13ab4a7efbaf6..71e05fed57dc0 100644
--- a/llvm/test/Transforms/SLPVectorizer/AArch64/splat-loads.ll
+++ b/llvm/test/Transforms/SLPVectorizer/AArch64/splat-loads.ll
@@ -10,20 +10,20 @@ define void @splat_loads_double(double *%array1, double *%array2, double *%ptrA,
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[GEP_1_0:%.*]] = getelementptr inbounds double, double* [[ARRAY1:%.*]], i64 0
 ; CHECK-NEXT:    [[GEP_2_0:%.*]] = getelementptr inbounds double, double* [[ARRAY2:%.*]], i64 0
+; CHECK-NEXT:    [[GEP_2_1:%.*]] = getelementptr inbounds double, double* [[ARRAY2]], i64 1
+; CHECK-NEXT:    [[LD_2_0:%.*]] = load double, double* [[GEP_2_0]], align 8
+; CHECK-NEXT:    [[LD_2_1:%.*]] = load double, double* [[GEP_2_1]], align 8
 ; CHECK-NEXT:    [[TMP0:%.*]] = bitcast double* [[GEP_1_0]] to <2 x double>*
 ; CHECK-NEXT:    [[TMP1:%.*]] = load <2 x double>, <2 x double>* [[TMP0]], align 8
-; CHECK-NEXT:    [[TMP2:%.*]] = bitcast double* [[GEP_2_0]] to <2 x double>*
-; CHECK-NEXT:    [[TMP3:%.*]] = load <2 x double>, <2 x double>* [[TMP2]], align 8
-; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <2 x double> [[TMP3]], <2 x double> poison, <2 x i32> <i32 1, i32 0>
-; CHECK-NEXT:    [[TMP4:%.*]] = fmul <2 x double> [[TMP1]], [[SHUFFLE]]
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x double> [[SHUFFLE]], i32 1
-; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x double> poison, double [[TMP5]], i32 0
-; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x double> [[SHUFFLE]], i32 0
-; CHECK-NEXT:    [[TMP8:%.*]] = insertelement <2 x double> [[TMP6]], double [[TMP7]], i32 1
-; CHECK-NEXT:    [[TMP9:%.*]] = fmul <2 x double> [[TMP1]], [[TMP8]]
-; CHECK-NEXT:    [[TMP10:%.*]] = fadd <2 x double> [[TMP4]], [[TMP9]]
-; CHECK-NEXT:    [[TMP11:%.*]] = bitcast double* [[GEP_1_0]] to <2 x double>*
-; CHECK-NEXT:    store <2 x double> [[TMP10]], <2 x double>* [[TMP11]], align 8
+; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <2 x double> poison, double [[LD_2_0]], i32 0
+; CHECK-NEXT:    [[TMP3:%.*]] = insertelement <2 x double> [[TMP2]], double [[LD_2_0]], i32 1
+; CHECK-NEXT:    [[TMP4:%.*]] = fmul <2 x double> [[TMP1]], [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = insertelement <2 x double> poison, double [[LD_2_1]], i32 0
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x double> [[TMP5]], double [[LD_2_1]], i32 1
+; CHECK-NEXT:    [[TMP7:%.*]] = fmul <2 x double> [[TMP1]], [[TMP6]]
+; CHECK-NEXT:    [[TMP8:%.*]] = fadd <2 x double> [[TMP4]], [[TMP7]]
+; CHECK-NEXT:    [[TMP9:%.*]] = bitcast double* [[GEP_1_0]] to <2 x double>*
+; CHECK-NEXT:    store <2 x double> [[TMP8]], <2 x double>* [[TMP9]], align 8
 ; CHECK-NEXT:    ret void
 ;
 entry:
@@ -57,20 +57,20 @@ define void @splat_loads_float(float *%array1, float *%array2, float *%ptrA, flo
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[GEP_1_0:%.*]] = getelementptr inbounds float, float* [[ARRAY1:%.*]], i64 0
 ; CHECK-NEXT:    [[GEP_2_0:%.*]] = getelementptr inbounds float, float* [[ARRAY2:%.*]], i64 0
+; CHECK-NEXT:    [[GEP_2_1:%.*]] = getelementptr inbounds float, float* [[ARRAY2]], i64 1
+; CHECK-NEXT:    [[LD_2_0:%.*]] = load float, float* [[GEP_2_0]], align 8
+; CHECK-NEXT:    [[LD_2_1:%.*]] = load float, float* [[GEP_2_1]], align 8
 ; CHECK-NEXT:    [[TMP0:%.*]] = bitcast float* [[GEP_1_0]] to <2 x float>*
 ; CHECK-NEXT:    [[TMP1:%.*]] = load <2 x float>, <2 x float>* [[TMP0]], align 8
-; CHECK-NEXT:    [[TMP2:%.*]] = bitcast float* [[GEP_2_0]] to <2 x float>*
-; CHECK-NEXT:    [[TMP3:%.*]] = load <2 x float>, <2 x float>* [[TMP2]], align 8
-; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <2 x float> [[TMP3]], <2 x float> poison, <2 x i32> <i32 1, i32 0>
-; CHECK-NEXT:    [[TMP4:%.*]] = fmul <2 x float> [[TMP1]], [[SHUFFLE]]
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x float> [[SHUFFLE]], i32 1
-; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x float> poison, float [[TMP5]], i32 0
-; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x float> [[SHUFFLE]], i32 0
-; CHECK-NEXT:    [[TMP8:%.*]] = insertelement <2 x float> [[TMP6]], float [[TMP7]], i32 1
-; CHECK-NEXT:    [[TMP9:%.*]] = fmul <2 x float> [[TMP1]], [[TMP8]]
-; CHECK-NEXT:    [[TMP10:%.*]] = fadd <2 x float> [[TMP4]], [[TMP9]]
-; CHECK-NEXT:    [[TMP11:%.*]] = bitcast float* [[GEP_1_0]] to <2 x float>*
-; CHECK-NEXT:    store <2 x float> [[TMP10]], <2 x float>* [[TMP11]], align 4
+; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <2 x float> poison, float [[LD_2_0]], i32 0
+; CHECK-NEXT:    [[TMP3:%.*]] = insertelement <2 x float> [[TMP2]], float [[LD_2_0]], i32 1
+; CHECK-NEXT:    [[TMP4:%.*]] = fmul <2 x float> [[TMP1]], [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = insertelement <2 x float> poison, float [[LD_2_1]], i32 0
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x float> [[TMP5]], float [[LD_2_1]], i32 1
+; CHECK-NEXT:    [[TMP7:%.*]] = fmul <2 x float> [[TMP1]], [[TMP6]]
+; CHECK-NEXT:    [[TMP8:%.*]] = fadd <2 x float> [[TMP4]], [[TMP7]]
+; CHECK-NEXT:    [[TMP9:%.*]] = bitcast float* [[GEP_1_0]] to <2 x float>*
+; CHECK-NEXT:    store <2 x float> [[TMP8]], <2 x float>* [[TMP9]], align 4
 ; CHECK-NEXT:    ret void
 ;
 entry:
@@ -104,20 +104,20 @@ define void @splat_loads_i64(i64 *%array1, i64 *%array2, i64 *%ptrA, i64 *%ptrB)
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[GEP_1_0:%.*]] = getelementptr inbounds i64, i64* [[ARRAY1:%.*]], i64 0
 ; CHECK-NEXT:    [[GEP_2_0:%.*]] = getelementptr inbounds i64, i64* [[ARRAY2:%.*]], i64 0
+; CHECK-NEXT:    [[GEP_2_1:%.*]] = getelementptr inbounds i64, i64* [[ARRAY2]], i64 1
+; CHECK-NEXT:    [[LD_2_0:%.*]] = load i64, i64* [[GEP_2_0]], align 8
+; CHECK-NEXT:    [[LD_2_1:%.*]] = load i64, i64* [[GEP_2_1]], align 8
 ; CHECK-NEXT:    [[TMP0:%.*]] = bitcast i64* [[GEP_1_0]] to <2 x i64>*
 ; CHECK-NEXT:    [[TMP1:%.*]] = load <2 x i64>, <2 x i64>* [[TMP0]], align 8
-; CHECK-NEXT:    [[TMP2:%.*]] = bitcast i64* [[GEP_2_0]] to <2 x i64>*
-; CHECK-NEXT:    [[TMP3:%.*]] = load <2 x i64>, <2 x i64>* [[TMP2]], align 8
-; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <2 x i64> [[TMP3]], <2 x i64> poison, <2 x i32> <i32 1, i32 0>
-; CHECK-NEXT:    [[TMP4:%.*]] = or <2 x i64> [[TMP1]], [[SHUFFLE]]
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x i64> [[SHUFFLE]], i32 1
-; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i64> poison, i64 [[TMP5]], i32 0
-; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x i64> [[SHUFFLE]], i32 0
-; CHECK-NEXT:    [[TMP8:%.*]] = insertelement <2 x i64> [[TMP6]], i64 [[TMP7]], i32 1
-; CHECK-NEXT:    [[TMP9:%.*]] = or <2 x i64> [[TMP1]], [[TMP8]]
-; CHECK-NEXT:    [[TMP10:%.*]] = add <2 x i64> [[TMP4]], [[TMP9]]
-; CHECK-NEXT:    [[TMP11:%.*]] = bitcast i64* [[GEP_1_0]] to <2 x i64>*
-; CHECK-NEXT:    store <2 x i64> [[TMP10]], <2 x i64>* [[TMP11]], align 4
+; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <2 x i64> poison, i64 [[LD_2_0]], i32 0
+; CHECK-NEXT:    [[TMP3:%.*]] = insertelement <2 x i64> [[TMP2]], i64 [[LD_2_0]], i32 1
+; CHECK-NEXT:    [[TMP4:%.*]] = or <2 x i64> [[TMP1]], [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = insertelement <2 x i64> poison, i64 [[LD_2_1]], i32 0
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i64> [[TMP5]], i64 [[LD_2_1]], i32 1
+; CHECK-NEXT:    [[TMP7:%.*]] = or <2 x i64> [[TMP1]], [[TMP6]]
+; CHECK-NEXT:    [[TMP8:%.*]] = add <2 x i64> [[TMP4]], [[TMP7]]
+; CHECK-NEXT:    [[TMP9:%.*]] = bitcast i64* [[GEP_1_0]] to <2 x i64>*
+; CHECK-NEXT:    store <2 x i64> [[TMP8]], <2 x i64>* [[TMP9]], align 4
 ; CHECK-NEXT:    ret void
 ;
 entry:
@@ -151,20 +151,20 @@ define void @splat_loads_i32(i32 *%array1, i32 *%array2, i32 *%ptrA, i32 *%ptrB)
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[GEP_1_0:%.*]] = getelementptr inbounds i32, i32* [[ARRAY1:%.*]], i64 0
 ; CHECK-NEXT:    [[GEP_2_0:%.*]] = getelementptr inbounds i32, i32* [[ARRAY2:%.*]], i64 0
+; CHECK-NEXT:    [[GEP_2_1:%.*]] = getelementptr inbounds i32, i32* [[ARRAY2]], i64 1
+; CHECK-NEXT:    [[LD_2_0:%.*]] = load i32, i32* [[GEP_2_0]], align 8
+; CHECK-NEXT:    [[LD_2_1:%.*]] = load i32, i32* [[GEP_2_1]], align 8
 ; CHECK-NEXT:    [[TMP0:%.*]] = bitcast i32* [[GEP_1_0]] to <2 x i32>*
 ; CHECK-NEXT:    [[TMP1:%.*]] = load <2 x i32>, <2 x i32>* [[TMP0]], align 8
-; CHECK-NEXT:    [[TMP2:%.*]] = bitcast i32* [[GEP_2_0]] to <2 x i32>*
-; CHECK-NEXT:    [[TMP3:%.*]] = load <2 x i32>, <2 x i32>* [[TMP2]], align 8
-; CHECK-NEXT:    [[SHUFFLE:%.*]] = shufflevector <2 x i32> [[TMP3]], <2 x i32> poison, <2 x i32> <i32 1, i32 0>
-; CHECK-NEXT:    [[TMP4:%.*]] = or <2 x i32> [[TMP1]], [[SHUFFLE]]
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x i32> [[SHUFFLE]], i32 1
-; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i32> poison, i32 [[TMP5]], i32 0
-; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x i32> [[SHUFFLE]], i32 0
-; CHECK-NEXT:    [[TMP8:%.*]] = insertelement <2 x i32> [[TMP6]], i32 [[TMP7]], i32 1
-; CHECK-NEXT:    [[TMP9:%.*]] = or <2 x i32> [[TMP1]], [[TMP8]]
-; CHECK-NEXT:    [[TMP10:%.*]] = add <2 x i32> [[TMP4]], [[TMP9]]
-; CHECK-NEXT:    [[TMP11:%.*]] = bitcast i32* [[GEP_1_0]] to <2 x i32>*
-; CHECK-NEXT:    store <2 x i32> [[TMP10]], <2 x i32>* [[TMP11]], align 4
+; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <2 x i32> poison, i32 [[LD_2_0]], i32 0
+; CHECK-NEXT:    [[TMP3:%.*]] = insertelement <2 x i32> [[TMP2]], i32 [[LD_2_0]], i32 1
+; CHECK-NEXT:    [[TMP4:%.*]] = or <2 x i32> [[TMP1]], [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = insertelement <2 x i32> poison, i32 [[LD_2_1]], i32 0
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i32> [[TMP5]], i32 [[LD_2_1]], i32 1
+; CHECK-NEXT:    [[TMP7:%.*]] = or <2 x i32> [[TMP1]], [[TMP6]]
+; CHECK-NEXT:    [[TMP8:%.*]] = add <2 x i32> [[TMP4]], [[TMP7]]
+; CHECK-NEXT:    [[TMP9:%.*]] = bitcast i32* [[GEP_1_0]] to <2 x i32>*
+; CHECK-NEXT:    store <2 x i32> [[TMP8]], <2 x i32>* [[TMP9]], align 4
 ; CHECK-NEXT:    ret void
 ;
 entry:


        


More information about the llvm-commits mailing list