[llvm-branch-commits] [llvm-branch] r261369 - Merging r261368:

Hans Wennborg via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Fri Feb 19 13:42:57 PST 2016


Author: hans
Date: Fri Feb 19 15:42:57 2016
New Revision: 261369

URL: http://llvm.org/viewvc/llvm-project?rev=261369&view=rev
Log:
Merging r261368:
------------------------------------------------------------------------
r261368 | hans | 2016-02-19 13:40:12 -0800 (Fri, 19 Feb 2016) | 3 lines

Revert r255691 "[LoopVectorizer] Refine loop vectorizer's register usage calculator by ignoring specific instructions."

It caused PR26509.
------------------------------------------------------------------------

Removed:
    llvm/branches/release_38/test/Transforms/LoopVectorize/X86/reg-usage.ll
Modified:
    llvm/branches/release_38/   (props changed)
    llvm/branches/release_38/lib/Transforms/Vectorize/LoopVectorize.cpp
    llvm/branches/release_38/test/Transforms/LoopVectorize/X86/vector_max_bandwidth.ll

Propchange: llvm/branches/release_38/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Fri Feb 19 15:42:57 2016
@@ -1,3 +1,3 @@
 /llvm/branches/Apple/Pertwee:110850,110961
 /llvm/branches/type-system-rewrite:133420-134817
-/llvm/trunk:155241,257645,257648,257730,257775,257791,257864,257875,257886,257902,257905,257925,257929-257930,257940,257942,257977,257979,257997,258103,258112,258168,258184,258207,258221,258273,258325,258406,258416,258428,258436,258471,258609-258611,258616,258690,258729,258891,258971,259177-259178,259228,259236,259342,259346,259375,259381,259645,259649,259695-259696,259702,259740,259798,259835,259840,259886,259888,259958,260164,260390,260427,260587,260641,260703,260733,261033,261039,261258,261306,261360,261365
+/llvm/trunk:155241,257645,257648,257730,257775,257791,257864,257875,257886,257902,257905,257925,257929-257930,257940,257942,257977,257979,257997,258103,258112,258168,258184,258207,258221,258273,258325,258406,258416,258428,258436,258471,258609-258611,258616,258690,258729,258891,258971,259177-259178,259228,259236,259342,259346,259375,259381,259645,259649,259695-259696,259702,259740,259798,259835,259840,259886,259888,259958,260164,260390,260427,260587,260641,260703,260733,261033,261039,261258,261306,261360,261365,261368

Modified: llvm/branches/release_38/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_38/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=261369&r1=261368&r2=261369&view=diff
==============================================================================
--- llvm/branches/release_38/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/branches/release_38/lib/Transforms/Vectorize/LoopVectorize.cpp Fri Feb 19 15:42:57 2016
@@ -1409,14 +1409,15 @@ private:
 /// different operations.
 class LoopVectorizationCostModel {
 public:
-  LoopVectorizationCostModel(Loop *L, PredicatedScalarEvolution &PSE,
-                             LoopInfo *LI, LoopVectorizationLegality *Legal,
+  LoopVectorizationCostModel(Loop *L, ScalarEvolution *SE, LoopInfo *LI,
+                             LoopVectorizationLegality *Legal,
                              const TargetTransformInfo &TTI,
                              const TargetLibraryInfo *TLI, DemandedBits *DB,
                              AssumptionCache *AC, const Function *F,
-                             const LoopVectorizeHints *Hints)
-      : TheLoop(L), PSE(PSE), LI(LI), Legal(Legal), TTI(TTI), TLI(TLI), DB(DB),
-        AC(AC), TheFunction(F), Hints(Hints) {}
+                             const LoopVectorizeHints *Hints,
+                             SmallPtrSetImpl<const Value *> &ValuesToIgnore)
+      : TheLoop(L), SE(SE), LI(LI), Legal(Legal), TTI(TTI), TLI(TLI), DB(DB),
+        TheFunction(F), Hints(Hints), ValuesToIgnore(ValuesToIgnore) {}
 
   /// Information about vectorization costs
   struct VectorizationFactor {
@@ -1464,9 +1465,6 @@ public:
   SmallVector<RegisterUsage, 8>
   calculateRegisterUsage(const SmallVector<unsigned, 8> &VFs);
 
-  /// Collect values we want to ignore in the cost model.
-  void collectValuesToIgnore();
-
 private:
   /// Returns the expected execution cost. The unit of the cost does
   /// not matter because we use the 'cost' units to compare different
@@ -1498,8 +1496,8 @@ public:
 
   /// The loop that we evaluate.
   Loop *TheLoop;
-  /// Predicated scalar evolution analysis.
-  PredicatedScalarEvolution &PSE;
+  /// Scev analysis.
+  ScalarEvolution *SE;
   /// Loop Info analysis.
   LoopInfo *LI;
   /// Vectorization legality.
@@ -1508,17 +1506,13 @@ public:
   const TargetTransformInfo &TTI;
   /// Target Library Info.
   const TargetLibraryInfo *TLI;
-  /// Demanded bits analysis.
+  /// Demanded bits analysis
   DemandedBits *DB;
-  /// Assumption cache.
-  AssumptionCache *AC;
   const Function *TheFunction;
-  /// Loop Vectorize Hint.
+  // Loop Vectorize Hint.
   const LoopVectorizeHints *Hints;
-  /// Values to ignore in the cost model.
-  SmallPtrSet<const Value *, 16> ValuesToIgnore;
-  /// Values to ignore in the cost model when VF > 1.
-  SmallPtrSet<const Value *, 16> VecValuesToIgnore;
+  // Values to ignore in the cost model.
+  const SmallPtrSetImpl<const Value *> &ValuesToIgnore;
 };
 
 /// \brief This holds vectorization requirements that must be verified late in
@@ -1763,10 +1757,19 @@ struct LoopVectorize : public FunctionPa
       return false;
     }
 
+    // Collect values we want to ignore in the cost model. This includes
+    // type-promoting instructions we identified during reduction detection.
+    SmallPtrSet<const Value *, 32> ValuesToIgnore;
+    CodeMetrics::collectEphemeralValues(L, AC, ValuesToIgnore);
+    for (auto &Reduction : *LVL.getReductionVars()) {
+      RecurrenceDescriptor &RedDes = Reduction.second;
+      SmallPtrSetImpl<Instruction *> &Casts = RedDes.getCastInsts();
+      ValuesToIgnore.insert(Casts.begin(), Casts.end());
+    }
+
     // Use the cost model.
-    LoopVectorizationCostModel CM(L, PSE, LI, &LVL, *TTI, TLI, DB, AC, F,
-                                  &Hints);
-    CM.collectValuesToIgnore();
+    LoopVectorizationCostModel CM(L, PSE.getSE(), LI, &LVL, *TTI, TLI, DB, AC,
+                                  F, &Hints, ValuesToIgnore);
 
     // Check the function attributes to find out if this function should be
     // optimized for size.
@@ -4744,7 +4747,7 @@ LoopVectorizationCostModel::selectVector
   }
 
   // Find the trip count.
-  unsigned TC = PSE.getSE()->getSmallConstantTripCount(TheLoop);
+  unsigned TC = SE->getSmallConstantTripCount(TheLoop);
   DEBUG(dbgs() << "LV: Found trip count: " << TC << '\n');
 
   MinBWs = computeMinimumValueSizes(TheLoop->getBlocks(), *DB, &TTI);
@@ -4946,7 +4949,7 @@ unsigned LoopVectorizationCostModel::sel
     return 1;
 
   // Do not interleave loops with a relatively small trip count.
-  unsigned TC = PSE.getSE()->getSmallConstantTripCount(TheLoop);
+  unsigned TC = SE->getSmallConstantTripCount(TheLoop);
   if (TC > 1 && TC < TinyTripCountInterleaveThreshold)
     return 1;
 
@@ -5174,15 +5177,15 @@ LoopVectorizationCostModel::calculateReg
     // Ignore instructions that are never used within the loop.
     if (!Ends.count(I)) continue;
 
+    // Skip ignored values.
+    if (ValuesToIgnore.count(I))
+      continue;
+
     // Remove all of the instructions that end at this location.
     InstrList &List = TransposeEnds[i];
     for (unsigned int j = 0, e = List.size(); j < e; ++j)
       OpenIntervals.erase(List[j]);
 
-    // Skip ignored values.
-    if (ValuesToIgnore.count(I))
-      continue;
-
     // For each VF find the maximum usage of registers.
     for (unsigned j = 0, e = VFs.size(); j < e; ++j) {
       if (VFs[j] == 1) {
@@ -5192,12 +5195,8 @@ LoopVectorizationCostModel::calculateReg
 
       // Count the number of live intervals.
       unsigned RegUsage = 0;
-      for (auto Inst : OpenIntervals) {
-        // Skip ignored values for VF > 1.
-        if (VecValuesToIgnore.count(Inst))
-          continue;
+      for (auto Inst : OpenIntervals)
         RegUsage += GetRegUsage(Inst->getType(), VFs[j]);
-      }
       MaxUsages[j] = std::max(MaxUsages[j], RegUsage);
     }
 
@@ -5341,7 +5340,6 @@ LoopVectorizationCostModel::getInstructi
   if (VF > 1 && MinBWs.count(I))
     RetTy = IntegerType::get(RetTy->getContext(), MinBWs[I]);
   Type *VectorTy = ToVectorTy(RetTy, VF);
-  auto SE = PSE.getSE();
 
   // TODO: We need to estimate the cost of intrinsic calls.
   switch (I->getOpcode()) {
@@ -5643,79 +5641,6 @@ bool LoopVectorizationCostModel::isConse
   return false;
 }
 
-void LoopVectorizationCostModel::collectValuesToIgnore() {
-  // Ignore ephemeral values.
-  CodeMetrics::collectEphemeralValues(TheLoop, AC, ValuesToIgnore);
-
-  // Ignore type-promoting instructions we identified during reduction
-  // detection.
-  for (auto &Reduction : *Legal->getReductionVars()) {
-    RecurrenceDescriptor &RedDes = Reduction.second;
-    SmallPtrSetImpl<Instruction *> &Casts = RedDes.getCastInsts();
-    VecValuesToIgnore.insert(Casts.begin(), Casts.end());
-  }
-
-  // Ignore induction phis that are only used in either GetElementPtr or ICmp
-  // instruction to exit loop. Induction variables usually have large types and
-  // can have big impact when estimating register usage.
-  // This is for when VF > 1.
-  for (auto &Induction : *Legal->getInductionVars()) {
-    auto *PN = Induction.first;
-    auto *UpdateV = PN->getIncomingValueForBlock(TheLoop->getLoopLatch());
-
-    // Check that the PHI is only used by the induction increment (UpdateV) or
-    // by GEPs. Then check that UpdateV is only used by a compare instruction or
-    // the loop header PHI.
-    // FIXME: Need precise def-use analysis to determine if this instruction
-    // variable will be vectorized.
-    if (std::all_of(PN->user_begin(), PN->user_end(),
-                    [&](const User *U) -> bool {
-                      return U == UpdateV || isa<GetElementPtrInst>(U);
-                    }) &&
-        std::all_of(UpdateV->user_begin(), UpdateV->user_end(),
-                    [&](const User *U) -> bool {
-                      return U == PN || isa<ICmpInst>(U);
-                    })) {
-      VecValuesToIgnore.insert(PN);
-      VecValuesToIgnore.insert(UpdateV);
-    }
-  }
-
-  // Ignore instructions that will not be vectorized.
-  // This is for when VF > 1.
-  for (auto bb = TheLoop->block_begin(), be = TheLoop->block_end(); bb != be;
-       ++bb) {
-    for (auto &Inst : **bb) {
-      switch (Inst.getOpcode()) {
-      case Instruction::GetElementPtr: {
-        // Ignore GEP if its last operand is an induction variable so that it is
-        // a consecutive load/store and won't be vectorized as scatter/gather
-        // pattern.
-
-        GetElementPtrInst *Gep = cast<GetElementPtrInst>(&Inst);
-        unsigned NumOperands = Gep->getNumOperands();
-        unsigned InductionOperand = getGEPInductionOperand(Gep);
-        bool GepToIgnore = true;
-
-        // Check that all of the gep indices are uniform except for the
-        // induction operand.
-        for (unsigned i = 0; i != NumOperands; ++i) {
-          if (i != InductionOperand &&
-              !PSE.getSE()->isLoopInvariant(PSE.getSCEV(Gep->getOperand(i)),
-                                            TheLoop)) {
-            GepToIgnore = false;
-            break;
-          }
-        }
-
-        if (GepToIgnore)
-          VecValuesToIgnore.insert(&Inst);
-        break;
-      }
-      }
-    }
-  }
-}
 
 void InnerLoopUnroller::scalarizeInstruction(Instruction *Instr,
                                              bool IfPredicateStore) {

Removed: llvm/branches/release_38/test/Transforms/LoopVectorize/X86/reg-usage.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_38/test/Transforms/LoopVectorize/X86/reg-usage.ll?rev=261368&view=auto
==============================================================================
--- llvm/branches/release_38/test/Transforms/LoopVectorize/X86/reg-usage.ll (original)
+++ llvm/branches/release_38/test/Transforms/LoopVectorize/X86/reg-usage.ll (removed)
@@ -1,71 +0,0 @@
-; RUN: opt < %s -debug-only=loop-vectorize -loop-vectorize -vectorizer-maximize-bandwidth -O2 -S 2>&1 | FileCheck %s
-; REQUIRES: asserts
-
-target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
-target triple = "x86_64-unknown-linux-gnu"
-
- at a = global [1024 x i8] zeroinitializer, align 16
- at b = global [1024 x i8] zeroinitializer, align 16
-
-define i32 @foo() {
-; This function has a loop of SAD pattern. Here we check when VF = 16 the
-; register usage doesn't exceed 16.
-;
-; CHECK-LABEL: foo
-; CHECK:      LV(REG): VF = 4
-; CHECK-NEXT: LV(REG): Found max usage: 4
-; CHECK:      LV(REG): VF = 8
-; CHECK-NEXT: LV(REG): Found max usage: 7
-; CHECK:      LV(REG): VF = 16
-; CHECK-NEXT: LV(REG): Found max usage: 13
-
-entry:
-  br label %for.body
-
-for.cond.cleanup:
-  %add.lcssa = phi i32 [ %add, %for.body ]
-  ret i32 %add.lcssa
-
-for.body:
-  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
-  %s.015 = phi i32 [ 0, %entry ], [ %add, %for.body ]
-  %arrayidx = getelementptr inbounds [1024 x i8], [1024 x i8]* @a, i64 0, i64 %indvars.iv
-  %0 = load i8, i8* %arrayidx, align 1
-  %conv = zext i8 %0 to i32
-  %arrayidx2 = getelementptr inbounds [1024 x i8], [1024 x i8]* @b, i64 0, i64 %indvars.iv
-  %1 = load i8, i8* %arrayidx2, align 1
-  %conv3 = zext i8 %1 to i32
-  %sub = sub nsw i32 %conv, %conv3
-  %ispos = icmp sgt i32 %sub, -1
-  %neg = sub nsw i32 0, %sub
-  %2 = select i1 %ispos, i32 %sub, i32 %neg
-  %add = add nsw i32 %2, %s.015
-  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
-  %exitcond = icmp eq i64 %indvars.iv.next, 1024
-  br i1 %exitcond, label %for.cond.cleanup, label %for.body
-}
-
-define i64 @bar(i64* nocapture %a) {
-; CHECK-LABEL: bar
-; CHECK:       LV(REG): VF = 2
-; CHECK:       LV(REG): Found max usage: 4
-;
-entry:
-  br label %for.body
-
-for.cond.cleanup:
-  %add2.lcssa = phi i64 [ %add2, %for.body ]
-  ret i64 %add2.lcssa
-
-for.body:
-  %i.012 = phi i64 [ 0, %entry ], [ %inc, %for.body ]
-  %s.011 = phi i64 [ 0, %entry ], [ %add2, %for.body ]
-  %arrayidx = getelementptr inbounds i64, i64* %a, i64 %i.012
-  %0 = load i64, i64* %arrayidx, align 8
-  %add = add nsw i64 %0, %i.012
-  store i64 %add, i64* %arrayidx, align 8
-  %add2 = add nsw i64 %add, %s.011
-  %inc = add nuw nsw i64 %i.012, 1
-  %exitcond = icmp eq i64 %inc, 1024
-  br i1 %exitcond, label %for.cond.cleanup, label %for.body
-}

Modified: llvm/branches/release_38/test/Transforms/LoopVectorize/X86/vector_max_bandwidth.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_38/test/Transforms/LoopVectorize/X86/vector_max_bandwidth.ll?rev=261369&r1=261368&r2=261369&view=diff
==============================================================================
--- llvm/branches/release_38/test/Transforms/LoopVectorize/X86/vector_max_bandwidth.ll (original)
+++ llvm/branches/release_38/test/Transforms/LoopVectorize/X86/vector_max_bandwidth.ll Fri Feb 19 15:42:57 2016
@@ -16,7 +16,7 @@ target triple = "x86_64-unknown-linux-gn
 ; -vectorizer-maximize-bandwidth is indicated.
 ;
 ; CHECK-label: foo
-; CHECK: LV: Selecting VF: 32.
+; CHECK: LV: Selecting VF: 16.
 define void @foo() {
 entry:
   br label %for.body




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