[llvm] IVDesc: unify RecurKinds IAnyOf and FAnyOf (PR #118393)

Ramkumar Ramachandra via llvm-commits llvm-commits at lists.llvm.org
Mon Dec 16 02:44:05 PST 2024


https://github.com/artagnon updated https://github.com/llvm/llvm-project/pull/118393

>From 2c387ce73cb04392984f4ce5751f7122076e557f Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Mon, 2 Dec 2024 19:37:06 +0000
Subject: [PATCH] IVDescriptors: cut wasteful FAnyOf checking (NFC)

Checking RecurKind::FAnyOf in isRecurrenceDescriptor() is wasted work
when it already checks RecurKind::IAnyOf. Affect a minor adjustment to
the code to facilitate skipping the RecurKind::FAnyOf check, and strip
the check. The patch has the side-effect of rewriting some flaky code,
which would match an ICmp having the reduction phi as an operand with
IAnyOf, and due to NumCmpSelectPatternInst != 1 (the select redux is
also matched), it would have to rely on failing to match an FCmp with
FAnyOf, setting NumCmpSelectPatternInst = 1, and successfully
vectorizing an IAnyOf pattern with the incorrect debug output. There is
a test for this already in select-cmp.ll:
select_i32_from_icmp_same_inputs.
---
 llvm/include/llvm/Analysis/IVDescriptors.h    | 14 ++++----
 llvm/lib/Analysis/IVDescriptors.cpp           | 32 +++++++------------
 .../AArch64/AArch64TargetTransformInfo.cpp    |  3 +-
 .../Target/RISCV/RISCVTargetTransformInfo.h   |  3 +-
 .../Transforms/Vectorize/SLPVectorizer.cpp    | 10 +++---
 5 files changed, 25 insertions(+), 37 deletions(-)

diff --git a/llvm/include/llvm/Analysis/IVDescriptors.h b/llvm/include/llvm/Analysis/IVDescriptors.h
index e8041e22b031ce..ab4b35c081e27b 100644
--- a/llvm/include/llvm/Analysis/IVDescriptors.h
+++ b/llvm/include/llvm/Analysis/IVDescriptors.h
@@ -48,10 +48,8 @@ enum class RecurKind {
   FMinimum, ///< FP min with llvm.minimum semantics
   FMaximum, ///< FP max with llvm.maximum semantics
   FMulAdd,  ///< Sum of float products with llvm.fmuladd(a * b + sum).
-  IAnyOf,   ///< Any_of reduction with select(icmp(),x,y) where one of (x,y) is
-            ///< loop invariant, and both x and y are integer type.
-  FAnyOf,   ///< Any_of reduction with select(fcmp(),x,y) where one of (x,y) is
-            ///< loop invariant, and both x and y are integer type.
+  AnyOf,    ///< Any_of reduction with select(icmp(),x,y) where one of (x,y) is
+            ///< loop invariant.
   IFindLastIV, ///< FindLast reduction with select(icmp(),x,y) where one of
                ///< (x,y) is increasing loop induction, and both x and y are
                ///< integer type.
@@ -173,7 +171,7 @@ class RecurrenceDescriptor {
   static InstDesc isConditionalRdxPattern(RecurKind Kind, Instruction *I);
 
   /// Returns the opcode corresponding to the RecurrenceKind.
-  static unsigned getOpcode(RecurKind Kind);
+  static unsigned getOpcode(RecurKind Kind, Type *Ty);
 
   /// Returns true if Phi is a reduction of type Kind and adds it to the
   /// RecurrenceDescriptor. If either \p DB is non-null or \p AC and \p DT are
@@ -209,7 +207,9 @@ class RecurrenceDescriptor {
 
   RecurKind getRecurrenceKind() const { return Kind; }
 
-  unsigned getOpcode() const { return getOpcode(getRecurrenceKind()); }
+  unsigned getOpcode() const {
+    return getOpcode(getRecurrenceKind(), getRecurrenceType());
+  }
 
   FastMathFlags getFastMathFlags() const { return FMF; }
 
@@ -250,7 +250,7 @@ class RecurrenceDescriptor {
   /// Returns true if the recurrence kind is of the form
   ///   select(cmp(),x,y) where one of (x,y) is loop invariant.
   static bool isAnyOfRecurrenceKind(RecurKind Kind) {
-    return Kind == RecurKind::IAnyOf || Kind == RecurKind::FAnyOf;
+    return Kind == RecurKind::AnyOf;
   }
 
   /// Returns true if the recurrence kind is of the form
diff --git a/llvm/lib/Analysis/IVDescriptors.cpp b/llvm/lib/Analysis/IVDescriptors.cpp
index f74ede4450ce52..a63f36dc5c8f05 100644
--- a/llvm/lib/Analysis/IVDescriptors.cpp
+++ b/llvm/lib/Analysis/IVDescriptors.cpp
@@ -49,8 +49,7 @@ bool RecurrenceDescriptor::isIntegerRecurrenceKind(RecurKind Kind) {
   case RecurKind::SMin:
   case RecurKind::UMax:
   case RecurKind::UMin:
-  case RecurKind::IAnyOf:
-  case RecurKind::FAnyOf:
+  case RecurKind::AnyOf:
   case RecurKind::IFindLastIV:
   case RecurKind::FFindLastIV:
     return true;
@@ -417,11 +416,11 @@ bool RecurrenceDescriptor::AddReductionVar(
     if (IsAPhi && Cur != Phi && !areAllUsesIn(Cur, VisitedInsts))
       return false;
 
-    if ((isIntMinMaxRecurrenceKind(Kind) || Kind == RecurKind::IAnyOf) &&
-        (isa<ICmpInst>(Cur) || isa<SelectInst>(Cur)))
+    if ((isIntMinMaxRecurrenceKind(Kind) &&
+         (isa<ICmpInst>(Cur) || IsASelect)) ||
+        (isFPMinMaxRecurrenceKind(Kind) && (isa<FCmpInst>(Cur) || IsASelect)))
       ++NumCmpSelectPatternInst;
-    if ((isFPMinMaxRecurrenceKind(Kind) || Kind == RecurKind::FAnyOf) &&
-        (isa<FCmpInst>(Cur) || isa<SelectInst>(Cur)))
+    if (isAnyOfRecurrenceKind(Kind) && IsASelect)
       ++NumCmpSelectPatternInst;
 
     // Check  whether we found a reduction operator.
@@ -656,8 +655,7 @@ RecurrenceDescriptor::isAnyOfPattern(Loop *Loop, PHINode *OrigPhi,
   if (!Loop->isLoopInvariant(NonPhi))
     return InstDesc(false, I);
 
-  return InstDesc(I, isa<ICmpInst>(I->getOperand(0)) ? RecurKind::IAnyOf
-                                                     : RecurKind::FAnyOf);
+  return InstDesc(I, RecurKind::AnyOf);
 }
 
 // We are looking for loops that do something like this:
@@ -979,10 +977,10 @@ bool RecurrenceDescriptor::isReductionPHI(PHINode *Phi, Loop *TheLoop,
     LLVM_DEBUG(dbgs() << "Found a UMIN reduction PHI." << *Phi << "\n");
     return true;
   }
-  if (AddReductionVar(Phi, RecurKind::IAnyOf, TheLoop, FMF, RedDes, DB, AC, DT,
+  if (AddReductionVar(Phi, RecurKind::AnyOf, TheLoop, FMF, RedDes, DB, AC, DT,
                       SE)) {
-    LLVM_DEBUG(dbgs() << "Found an integer conditional select reduction PHI."
-                      << *Phi << "\n");
+    LLVM_DEBUG(dbgs() << "Found an conditional select reduction PHI." << *Phi
+                      << "\n");
     return true;
   }
   if (AddReductionVar(Phi, RecurKind::IFindLastIV, TheLoop, FMF, RedDes, DB, AC,
@@ -1014,12 +1012,6 @@ bool RecurrenceDescriptor::isReductionPHI(PHINode *Phi, Loop *TheLoop,
     LLVM_DEBUG(dbgs() << "Found a float MIN reduction PHI." << *Phi << "\n");
     return true;
   }
-  if (AddReductionVar(Phi, RecurKind::FAnyOf, TheLoop, FMF, RedDes, DB, AC, DT,
-                      SE)) {
-    LLVM_DEBUG(dbgs() << "Found a float conditional select reduction PHI."
-                      << " PHI." << *Phi << "\n");
-    return true;
-  }
   if (AddReductionVar(Phi, RecurKind::FMulAdd, TheLoop, FMF, RedDes, DB, AC, DT,
                       SE)) {
     LLVM_DEBUG(dbgs() << "Found an FMulAdd reduction PHI." << *Phi << "\n");
@@ -1127,7 +1119,7 @@ bool RecurrenceDescriptor::isFixedOrderRecurrence(PHINode *Phi, Loop *TheLoop,
   return true;
 }
 
-unsigned RecurrenceDescriptor::getOpcode(RecurKind Kind) {
+unsigned RecurrenceDescriptor::getOpcode(RecurKind Kind, Type *Ty) {
   switch (Kind) {
   case RecurKind::Add:
     return Instruction::Add;
@@ -1148,16 +1140,16 @@ unsigned RecurrenceDescriptor::getOpcode(RecurKind Kind) {
   case RecurKind::SMin:
   case RecurKind::UMax:
   case RecurKind::UMin:
-  case RecurKind::IAnyOf:
   case RecurKind::IFindLastIV:
     return Instruction::ICmp;
   case RecurKind::FMax:
   case RecurKind::FMin:
   case RecurKind::FMaximum:
   case RecurKind::FMinimum:
-  case RecurKind::FAnyOf:
   case RecurKind::FFindLastIV:
     return Instruction::FCmp;
+  case RecurKind::AnyOf:
+    return Ty->isIntegerTy() ? Instruction::ICmp : Instruction::FCmp;
   default:
     llvm_unreachable("Unknown recurrence operation");
   }
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index 6c2e04c3f8a7c1..6f12c569fac733 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -4318,8 +4318,7 @@ bool AArch64TTIImpl::isLegalToVectorizeReduction(
   case RecurKind::FMin:
   case RecurKind::FMax:
   case RecurKind::FMulAdd:
-  case RecurKind::IAnyOf:
-  case RecurKind::FAnyOf:
+  case RecurKind::AnyOf:
     return true;
   default:
     return false;
diff --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h
index bd90bfed6e2c95..e9dbd32d998f2d 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h
+++ b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h
@@ -348,8 +348,7 @@ class RISCVTTIImpl : public BasicTTIImplBase<RISCVTTIImpl> {
     case RecurKind::FMin:
     case RecurKind::FMax:
     case RecurKind::FMulAdd:
-    case RecurKind::IAnyOf:
-    case RecurKind::FAnyOf:
+    case RecurKind::AnyOf:
       return true;
     default:
       return false;
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 3bd983ee6e125d..0122f83659a8a2 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -19182,7 +19182,7 @@ class HorizontalReduction {
   /// Creates reduction operation with the current opcode.
   static Value *createOp(IRBuilderBase &Builder, RecurKind Kind, Value *LHS,
                          Value *RHS, const Twine &Name, bool UseSelect) {
-    unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(Kind);
+    unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(Kind, LHS->getType());
     switch (Kind) {
     case RecurKind::Or:
       if (UseSelect &&
@@ -20325,7 +20325,7 @@ class HorizontalReduction {
     case RecurKind::Xor:
     case RecurKind::FAdd:
     case RecurKind::FMul: {
-      unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(RdxKind);
+      unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(RdxKind, ScalarTy);
       if (!AllConsts) {
         if (auto *VecTy = dyn_cast<FixedVectorType>(ScalarTy)) {
           assert(SLPReVec && "FixedVectorType is not expected.");
@@ -20454,8 +20454,7 @@ class HorizontalReduction {
     case RecurKind::Mul:
     case RecurKind::FMul:
     case RecurKind::FMulAdd:
-    case RecurKind::IAnyOf:
-    case RecurKind::FAnyOf:
+    case RecurKind::AnyOf:
     case RecurKind::IFindLastIV:
     case RecurKind::FFindLastIV:
     case RecurKind::None:
@@ -20553,8 +20552,7 @@ class HorizontalReduction {
     case RecurKind::Mul:
     case RecurKind::FMul:
     case RecurKind::FMulAdd:
-    case RecurKind::IAnyOf:
-    case RecurKind::FAnyOf:
+    case RecurKind::AnyOf:
     case RecurKind::IFindLastIV:
     case RecurKind::FFindLastIV:
     case RecurKind::None:



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