[PATCH] D112562: [SLP]Fix logical and/or reductions.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev created this revision.
ABataev added reviewers: RKSimon, spatel, anton-afanasyev, dtemirbulatov.
Herald added a subscriber: hiraditya.
ABataev requested review of this revision.
Herald added a project: LLVM.

Need to emit select(cmp) instructions for poison-safe forms of select
ops. Currently alive reports that `Target is more poisonous than source`
for operations we generating for such instructions.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D112562

Files:
  llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  llvm/test/Transforms/SLPVectorizer/X86/reduction-logical.ll


Index: llvm/test/Transforms/SLPVectorizer/X86/reduction-logical.ll
===================================================================
--- llvm/test/Transforms/SLPVectorizer/X86/reduction-logical.ll
+++ llvm/test/Transforms/SLPVectorizer/X86/reduction-logical.ll
@@ -480,7 +480,7 @@
 ; CHECK-NEXT:    [[S3:%.*]] = select i1 [[C:%.*]], i1 [[C]], i1 false
 ; CHECK-NEXT:    [[TMP2:%.*]] = freeze <4 x i1> [[TMP1]]
 ; CHECK-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.and.v4i1(<4 x i1> [[TMP2]])
-; CHECK-NEXT:    [[OP_EXTRA:%.*]] = and i1 [[TMP3]], [[S3]]
+; CHECK-NEXT:    [[OP_EXTRA:%.*]] = select i1 [[TMP3]], i1 [[S3]], i1 false
 ; CHECK-NEXT:    ret i1 [[OP_EXTRA]]
 ;
   %x0 = extractelement <4 x i32> %x, i32 0
Index: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -8012,10 +8012,18 @@
                          Value *RHS, const Twine &Name, bool UseSelect) {
     unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(Kind);
     switch (Kind) {
-    case RecurKind::Add:
-    case RecurKind::Mul:
     case RecurKind::Or:
+      if (UseSelect &&
+          LHS->getType() == CmpInst::makeCmpResultType(LHS->getType()))
+        return Builder.CreateSelect(LHS, Builder.getTrue(), RHS, Name);
+      LLVM_FALLTHROUGH;
     case RecurKind::And:
+      if (UseSelect &&
+          LHS->getType() == CmpInst::makeCmpResultType(LHS->getType()))
+        return Builder.CreateSelect(LHS, RHS, Builder.getFalse(), Name);
+      LLVM_FALLTHROUGH;
+    case RecurKind::Add:
+    case RecurKind::Mul:
     case RecurKind::Xor:
     case RecurKind::FAdd:
     case RecurKind::FMul:
@@ -8059,8 +8067,12 @@
   static Value *createOp(IRBuilder<> &Builder, RecurKind RdxKind, Value *LHS,
                          Value *RHS, const Twine &Name,
                          const ReductionOpsListType &ReductionOps) {
-    bool UseSelect = ReductionOps.size() == 2;
-    assert((!UseSelect || isa<SelectInst>(ReductionOps[1][0])) &&
+    bool UseSelect = ReductionOps.size() == 2 ||
+                     // Logical or/and.
+                     (ReductionOps.size() == 1 &&
+                      isa<SelectInst>(ReductionOps.front().front()));
+    assert((!UseSelect || ReductionOps.size() != 2 ||
+            isa<SelectInst>(ReductionOps[1][0])) &&
            "Expected cmp + select pairs for reduction");
     Value *Op = createOp(Builder, RdxKind, LHS, RHS, Name, UseSelect);
     if (RecurrenceDescriptor::isIntMinMaxRecurrenceKind(RdxKind)) {
@@ -8198,10 +8210,10 @@
   /// Checks if the instruction is in basic block \p BB.
   /// For a cmp+sel min/max reduction check that both ops are in \p BB.
   static bool hasSameParent(Instruction *I, BasicBlock *BB) {
-    if (isCmpSelMinMax(I)) {
+    if (isCmpSelMinMax(I) || (isBoolLogicOp(I) && isa<SelectInst>(I))) {
       auto *Sel = cast<SelectInst>(I);
-      auto *Cmp = cast<Instruction>(Sel->getCondition());
-      return Sel->getParent() == BB && Cmp->getParent() == BB;
+      auto *Cmp = dyn_cast<Instruction>(Sel->getCondition());
+      return Sel->getParent() == BB && Cmp && Cmp->getParent() == BB;
     }
     return I->getParent() == BB;
   }


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