[X86][AVX512] Add 512-bit vector ctlz costs + tests

llvm-svn: 303300

llvm/lib/Target/X86/X86TargetTransformInfo.cpp

@@ -1392,11 +1392,29 @@ int X86TTIImpl::getIntrinsicInstrCost(Intrinsic::ID IID, Type *RetTy,
   // CTLZ: llvm\test\CodeGen\X86\vector-lzcnt-*.ll
   // CTPOP: llvm\test\CodeGen\X86\vector-popcnt-*.ll
   // CTTZ: llvm\test\CodeGen\X86\vector-tzcnt-*.ll
+  static const CostTblEntry AVX512CDCostTbl[] = {
+    { ISD::CTLZ,       MVT::v8i64,   1 },
+    { ISD::CTLZ,       MVT::v16i32,  1 },
+    { ISD::CTLZ,       MVT::v32i16,  8 },
+    { ISD::CTLZ,       MVT::v64i8,  20 },
+    { ISD::CTLZ,       MVT::v4i64,   1 },
+    { ISD::CTLZ,       MVT::v8i32,   1 },
+    { ISD::CTLZ,       MVT::v16i16,  4 },
+    { ISD::CTLZ,       MVT::v32i8,  10 },
+    { ISD::CTLZ,       MVT::v2i64,   1 },
+    { ISD::CTLZ,       MVT::v4i32,   1 },
+    { ISD::CTLZ,       MVT::v8i16,   4 },
+    { ISD::CTLZ,       MVT::v16i8,   4 },
+  };
   static const CostTblEntry AVX512BWCostTbl[] = {
     { ISD::BITREVERSE, MVT::v8i64,   5 },
     { ISD::BITREVERSE, MVT::v16i32,  5 },
     { ISD::BITREVERSE, MVT::v32i16,  5 },
     { ISD::BITREVERSE, MVT::v64i8,   5 },
+    { ISD::CTLZ,       MVT::v8i64,  23 },
+    { ISD::CTLZ,       MVT::v16i32, 22 },
+    { ISD::CTLZ,       MVT::v32i16, 18 },
+    { ISD::CTLZ,       MVT::v64i8,  17 },
     { ISD::CTTZ,       MVT::v8i64,  10 },
     { ISD::CTTZ,       MVT::v16i32, 14 },
     { ISD::CTTZ,       MVT::v32i16, 12 },
@@ -1405,6 +1423,8 @@ int X86TTIImpl::getIntrinsicInstrCost(Intrinsic::ID IID, Type *RetTy,
   static const CostTblEntry AVX512CostTbl[] = {
     { ISD::BITREVERSE, MVT::v8i64,  36 },
     { ISD::BITREVERSE, MVT::v16i32, 24 },
+    { ISD::CTLZ,       MVT::v8i64,  29 },
+    { ISD::CTLZ,       MVT::v16i32, 35 },
     { ISD::CTTZ,       MVT::v8i64,  20 },
     { ISD::CTTZ,       MVT::v16i32, 28 },
   };
@@ -1566,6 +1586,10 @@ int X86TTIImpl::getIntrinsicInstrCost(Intrinsic::ID IID, Type *RetTy,
   MVT MTy = LT.second;
 
   // Attempt to lookup cost.
+  if (ST->hasCDI())
+    if (const auto *Entry = CostTableLookup(AVX512CDCostTbl, ISD, MTy))
+      return LT.first * Entry->Cost;
+
   if (ST->hasBWI())
     if (const auto *Entry = CostTableLookup(AVX512BWCostTbl, ISD, MTy))
       return LT.first * Entry->Cost;

llvm/test/Analysis/CostModel/X86/ctlz.ll

@@ -1,9 +1,12 @@
-; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=pentium4 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=SSE -check-prefix=SSE2 -check-prefix=NOPOPCNT
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=pentium4 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=SSE -check-prefix=SSE2
-; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=SSE -check-prefix=SSE42 -check-prefix=POPCNT
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=SSE -check-prefix=SSE42
-; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7-avx -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX1 -check-prefix=POPCNT
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=corei7-avx -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX1
-; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=core-avx2 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX2 -check-prefix=POPCNT
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=core-avx2 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX2
-; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=bdver2 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX1 -check-prefix=POPCNT
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=bdver2 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX1
-; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=bdver4 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX2 -check-prefix=POPCNT
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=bdver4 -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX -check-prefix=AVX2
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=knl -mattr=-avx512cd -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX512 -check-prefix=AVX512F
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=skx -mattr=-avx512cd -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX512 -check-prefix=AVX512BW
+; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=skx -mattr=+avx512cd -cost-model -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=AVX512CD
 
 ; Verify the cost of scalar leading zero count instructions.
 
@@ -80,11 +83,18 @@ declare <8 x i32> @llvm.ctlz.v8i32(<8 x i32>, i1)
 declare <16 x i16> @llvm.ctlz.v16i16(<16 x i16>, i1)
 declare <32 x i8> @llvm.ctlz.v32i8(<32 x i8>, i1)
 
+declare <8 x i64> @llvm.ctlz.v8i64(<8 x i64>, i1)
+declare <16 x i32> @llvm.ctlz.v16i32(<16 x i32>, i1)
+declare <32 x i16> @llvm.ctlz.v32i16(<32 x i16>, i1)
+declare <64 x i8> @llvm.ctlz.v64i8(<64 x i8>, i1)
+
 define <2 x i64> @var_ctlz_v2i64(<2 x i64> %a) {
 ; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v2i64':
 ; SSE2: Found an estimated cost of 25 for instruction:   %ctlz
 ; SSE42: Found an estimated cost of 23 for instruction:   %ctlz
 ; AVX: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
   %ctlz = call <2 x i64> @llvm.ctlz.v2i64(<2 x i64> %a, i1 0)
   ret <2 x i64> %ctlz
 }
@@ -94,6 +104,8 @@ define <2 x i64> @var_ctlz_v2i64u(<2 x i64> %a) {
 ; SSE2: Found an estimated cost of 25 for instruction:   %ctlz
 ; SSE42: Found an estimated cost of 23 for instruction:   %ctlz
 ; AVX: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
   %ctlz = call <2 x i64> @llvm.ctlz.v2i64(<2 x i64> %a, i1 1)
   ret <2 x i64> %ctlz
 }
@@ -104,6 +116,8 @@ define <4 x i64> @var_ctlz_v4i64(<4 x i64> %a) {
 ; SSE42: Found an estimated cost of 46 for instruction:   %ctlz
 ; AVX1: Found an estimated cost of 48 for instruction:   %ctlz
 ; AVX2: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
   %ctlz = call <4 x i64> @llvm.ctlz.v4i64(<4 x i64> %a, i1 0)
   ret <4 x i64> %ctlz
 }
@@ -114,15 +128,45 @@ define <4 x i64> @var_ctlz_v4i64u(<4 x i64> %a) {
 ; SSE42: Found an estimated cost of 46 for instruction:   %ctlz
 ; AVX1: Found an estimated cost of 48 for instruction:   %ctlz
 ; AVX2: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
   %ctlz = call <4 x i64> @llvm.ctlz.v4i64(<4 x i64> %a, i1 1)
   ret <4 x i64> %ctlz
 }
 
+define <8 x i64> @var_ctlz_v8i64(<8 x i64> %a) {
+; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v8i64':
+; SSE2: Found an estimated cost of 100 for instruction:   %ctlz
+; SSE42: Found an estimated cost of 92 for instruction:   %ctlz
+; AVX1: Found an estimated cost of 96 for instruction:   %ctlz
+; AVX2: Found an estimated cost of 46 for instruction:   %ctlz
+; AVX512F: Found an estimated cost of 29 for instruction:   %ctlz
+; AVX512BW: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
+  %ctlz = call <8 x i64> @llvm.ctlz.v8i64(<8 x i64> %a, i1 0)
+  ret <8 x i64> %ctlz
+}
+
+define <8 x i64> @var_ctlz_v8i64u(<8 x i64> %a) {
+; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v8i64u':
+; SSE2: Found an estimated cost of 100 for instruction:   %ctlz
+; SSE42: Found an estimated cost of 92 for instruction:   %ctlz
+; AVX1: Found an estimated cost of 96 for instruction:   %ctlz
+; AVX2: Found an estimated cost of 46 for instruction:   %ctlz
+; AVX512F: Found an estimated cost of 29 for instruction:   %ctlz
+; AVX512BW: Found an estimated cost of 23 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
+  %ctlz = call <8 x i64> @llvm.ctlz.v8i64(<8 x i64> %a, i1 1)
+  ret <8 x i64> %ctlz
+}
+
 define <4 x i32> @var_ctlz_v4i32(<4 x i32> %a) {
 ; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v4i32':
 ; SSE2: Found an estimated cost of 26 for instruction:   %ctlz
 ; SSE42: Found an estimated cost of 18 for instruction:   %ctlz
 ; AVX: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
   %ctlz = call <4 x i32> @llvm.ctlz.v4i32(<4 x i32> %a, i1 0)
   ret <4 x i32> %ctlz
 }
@@ -132,6 +176,8 @@ define <4 x i32> @var_ctlz_v4i32u(<4 x i32> %a) {
 ; SSE2: Found an estimated cost of 26 for instruction:   %ctlz
 ; SSE42: Found an estimated cost of 18 for instruction:   %ctlz
 ; AVX: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
   %ctlz = call <4 x i32> @llvm.ctlz.v4i32(<4 x i32> %a, i1 1)
   ret <4 x i32> %ctlz
 }
@@ -142,6 +188,8 @@ define <8 x i32> @var_ctlz_v8i32(<8 x i32> %a) {
 ; SSE42: Found an estimated cost of 36 for instruction:   %ctlz
 ; AVX1: Found an estimated cost of 38 for instruction:   %ctlz
 ; AVX2: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
   %ctlz = call <8 x i32> @llvm.ctlz.v8i32(<8 x i32> %a, i1 0)
   ret <8 x i32> %ctlz
 }
@@ -152,15 +200,45 @@ define <8 x i32> @var_ctlz_v8i32u(<8 x i32> %a) {
 ; SSE42: Found an estimated cost of 36 for instruction:   %ctlz
 ; AVX1: Found an estimated cost of 38 for instruction:   %ctlz
 ; AVX2: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
   %ctlz = call <8 x i32> @llvm.ctlz.v8i32(<8 x i32> %a, i1 1)
   ret <8 x i32> %ctlz
 }
 
+define <16 x i32> @var_ctlz_v16i32(<16 x i32> %a) {
+; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v16i32':
+; SSE2: Found an estimated cost of 104 for instruction:   %ctlz
+; SSE42: Found an estimated cost of 72 for instruction:   %ctlz
+; AVX1: Found an estimated cost of 76 for instruction:   %ctlz
+; AVX2: Found an estimated cost of 36 for instruction:   %ctlz
+; AVX512F: Found an estimated cost of 35 for instruction:   %ctlz
+; AVX512BW: Found an estimated cost of 22 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
+  %ctlz = call <16 x i32> @llvm.ctlz.v16i32(<16 x i32> %a, i1 0)
+  ret <16 x i32> %ctlz
+}
+
+define <16 x i32> @var_ctlz_v16i32u(<16 x i32> %a) {
+; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v16i32u':
+; SSE2: Found an estimated cost of 104 for instruction:   %ctlz
+; SSE42: Found an estimated cost of 72 for instruction:   %ctlz
+; AVX1: Found an estimated cost of 76 for instruction:   %ctlz
+; AVX2: Found an estimated cost of 36 for instruction:   %ctlz
+; AVX512F: Found an estimated cost of 35 for instruction:   %ctlz
+; AVX512BW: Found an estimated cost of 22 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 1 for instruction:   %ctlz
+  %ctlz = call <16 x i32> @llvm.ctlz.v16i32(<16 x i32> %a, i1 1)
+  ret <16 x i32> %ctlz
+}
+
 define <8 x i16> @var_ctlz_v8i16(<8 x i16> %a) {
 ; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v8i16':
 ; SSE2: Found an estimated cost of 20 for instruction:   %ctlz
 ; SSE42: Found an estimated cost of 14 for instruction:   %ctlz
 ; AVX: Found an estimated cost of 14 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 14 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 4 for instruction:   %ctlz
   %ctlz = call <8 x i16> @llvm.ctlz.v8i16(<8 x i16> %a, i1 0)
   ret <8 x i16> %ctlz
 }
@@ -170,6 +248,8 @@ define <8 x i16> @var_ctlz_v8i16u(<8 x i16> %a) {
 ; SSE2: Found an estimated cost of 20 for instruction:   %ctlz
 ; SSE42: Found an estimated cost of 14 for instruction:   %ctlz
 ; AVX: Found an estimated cost of 14 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 14 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 4 for instruction:   %ctlz
   %ctlz = call <8 x i16> @llvm.ctlz.v8i16(<8 x i16> %a, i1 1)
   ret <8 x i16> %ctlz
 }
@@ -180,6 +260,8 @@ define <16 x i16> @var_ctlz_v16i16(<16 x i16> %a) {
 ; SSE42: Found an estimated cost of 28 for instruction:   %ctlz
 ; AVX1: Found an estimated cost of 30 for instruction:   %ctlz
 ; AVX2: Found an estimated cost of 14 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 14 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 4 for instruction:   %ctlz
   %ctlz = call <16 x i16> @llvm.ctlz.v16i16(<16 x i16> %a, i1 0)
   ret <16 x i16> %ctlz
 }
@@ -190,15 +272,45 @@ define <16 x i16> @var_ctlz_v16i16u(<16 x i16> %a) {
 ; SSE42: Found an estimated cost of 28 for instruction:   %ctlz
 ; AVX1: Found an estimated cost of 30 for instruction:   %ctlz
 ; AVX2: Found an estimated cost of 14 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 14 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 4 for instruction:   %ctlz
   %ctlz = call <16 x i16> @llvm.ctlz.v16i16(<16 x i16> %a, i1 1)
   ret <16 x i16> %ctlz
 }
 
+define <32 x i16> @var_ctlz_v32i16(<32 x i16> %a) {
+; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v32i16':
+; SSE2: Found an estimated cost of 80 for instruction:   %ctlz
+; SSE42: Found an estimated cost of 56 for instruction:   %ctlz
+; AVX1: Found an estimated cost of 60 for instruction:   %ctlz
+; AVX2: Found an estimated cost of 28 for instruction:   %ctlz
+; AVX512F: Found an estimated cost of 28 for instruction:   %ctlz
+; AVX512BW: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 8 for instruction:   %ctlz
+  %ctlz = call <32 x i16> @llvm.ctlz.v32i16(<32 x i16> %a, i1 0)
+  ret <32 x i16> %ctlz
+}
+
+define <32 x i16> @var_ctlz_v32i16u(<32 x i16> %a) {
+; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v32i16u':
+; SSE2: Found an estimated cost of 80 for instruction:   %ctlz
+; SSE42: Found an estimated cost of 56 for instruction:   %ctlz
+; AVX1: Found an estimated cost of 60 for instruction:   %ctlz
+; AVX2: Found an estimated cost of 28 for instruction:   %ctlz
+; AVX512F: Found an estimated cost of 28 for instruction:   %ctlz
+; AVX512BW: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 8 for instruction:   %ctlz
+  %ctlz = call <32 x i16> @llvm.ctlz.v32i16(<32 x i16> %a, i1 1)
+  ret <32 x i16> %ctlz
+}
+
 define <16 x i8> @var_ctlz_v16i8(<16 x i8> %a) {
 ; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v16i8':
 ; SSE2: Found an estimated cost of 17 for instruction:   %ctlz
 ; SSE42: Found an estimated cost of 9 for instruction:   %ctlz
 ; AVX: Found an estimated cost of 9 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 9 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 4 for instruction:   %ctlz
   %ctlz = call <16 x i8> @llvm.ctlz.v16i8(<16 x i8> %a, i1 0)
   ret <16 x i8> %ctlz
 }
@@ -208,6 +320,8 @@ define <16 x i8> @var_ctlz_v16i8u(<16 x i8> %a) {
 ; SSE2: Found an estimated cost of 17 for instruction:   %ctlz
 ; SSE42: Found an estimated cost of 9 for instruction:   %ctlz
 ; AVX: Found an estimated cost of 9 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 9 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 4 for instruction:   %ctlz
   %ctlz = call <16 x i8> @llvm.ctlz.v16i8(<16 x i8> %a, i1 1)
   ret <16 x i8> %ctlz
 }
@@ -218,6 +332,8 @@ define <32 x i8> @var_ctlz_v32i8(<32 x i8> %a) {
 ; SSE42: Found an estimated cost of 18 for instruction:   %ctlz
 ; AVX1: Found an estimated cost of 20 for instruction:   %ctlz
 ; AVX2: Found an estimated cost of 9 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 9 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 10 for instruction:   %ctlz
   %ctlz = call <32 x i8> @llvm.ctlz.v32i8(<32 x i8> %a, i1 0)
   ret <32 x i8> %ctlz
 }
@@ -228,6 +344,34 @@ define <32 x i8> @var_ctlz_v32i8u(<32 x i8> %a) {
 ; SSE42: Found an estimated cost of 18 for instruction:   %ctlz
 ; AVX1: Found an estimated cost of 20 for instruction:   %ctlz
 ; AVX2: Found an estimated cost of 9 for instruction:   %ctlz
+; AVX512: Found an estimated cost of 9 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 10 for instruction:   %ctlz
   %ctlz = call <32 x i8> @llvm.ctlz.v32i8(<32 x i8> %a, i1 1)
   ret <32 x i8> %ctlz
 }
+
+define <64 x i8> @var_ctlz_v64i8(<64 x i8> %a) {
+; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v64i8':
+; SSE2: Found an estimated cost of 68 for instruction:   %ctlz
+; SSE42: Found an estimated cost of 36 for instruction:   %ctlz
+; AVX1: Found an estimated cost of 40 for instruction:   %ctlz
+; AVX2: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512F: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512BW: Found an estimated cost of 17 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 20 for instruction:   %ctlz
+  %ctlz = call <64 x i8> @llvm.ctlz.v64i8(<64 x i8> %a, i1 0)
+  ret <64 x i8> %ctlz
+}
+
+define <64 x i8> @var_ctlz_v64i8u(<64 x i8> %a) {
+; CHECK: 'Cost Model Analysis' for function 'var_ctlz_v64i8u':
+; SSE2: Found an estimated cost of 68 for instruction:   %ctlz
+; SSE42: Found an estimated cost of 36 for instruction:   %ctlz
+; AVX1: Found an estimated cost of 40 for instruction:   %ctlz
+; AVX2: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512F: Found an estimated cost of 18 for instruction:   %ctlz
+; AVX512BW: Found an estimated cost of 17 for instruction:   %ctlz
+; AVX512CD: Found an estimated cost of 20 for instruction:   %ctlz
+  %ctlz = call <64 x i8> @llvm.ctlz.v64i8(<64 x i8> %a, i1 1)
+  ret <64 x i8> %ctlz
+}