[TTI] Add supportsScalableVectors target hook

This is split off from D91718 and adds a new target hook supportsScalableVectors that can be queried to check if scalable vectors are supported by the backend. For AArch64 this returns true if SVE is enabled. Reviewed By: david-arm Differential Revision: https://reviews.llvm.org/D93060
llvm · Dec 18, 2020 · 7c8796f · 7c8796f
1 parent 9899319
commit 7c8796f
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Showing 4 changed files with 16 additions and 0 deletions.
diff --git a/llvm/include/llvm/Analysis/TargetTransformInfo.h b/llvm/include/llvm/Analysis/TargetTransformInfo.h
@@ -1340,6 +1340,9 @@ class TargetTransformInfo {
   /// to a stack reload.
   unsigned getGISelRematGlobalCost() const;
 
+  /// \returns True if the target supports scalable vectors.
+  bool supportsScalableVectors() const;
+
   /// \name Vector Predication Information
   /// @{
   /// Whether the target supports the %evl parameter of VP intrinsic efficiently
@@ -1634,6 +1637,7 @@ class TargetTransformInfo::Concept {
                                                ReductionFlags) const = 0;
   virtual bool shouldExpandReduction(const IntrinsicInst *II) const = 0;
   virtual unsigned getGISelRematGlobalCost() const = 0;
+  virtual bool supportsScalableVectors() const = 0;
   virtual bool hasActiveVectorLength() const = 0;
   virtual int getInstructionLatency(const Instruction *I) = 0;
 };
@@ -2163,6 +2167,10 @@ class TargetTransformInfo::Model final : public TargetTransformInfo::Concept {
     return Impl.getGISelRematGlobalCost();
   }
 
+  bool supportsScalableVectors() const override {
+    return Impl.supportsScalableVectors();
+  }
+
   bool hasActiveVectorLength() const override {
     return Impl.hasActiveVectorLength();
   }

diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -685,6 +685,8 @@ class TargetTransformInfoImplBase {
 
   unsigned getGISelRematGlobalCost() const { return 1; }
 
+  bool supportsScalableVectors() const { return false; }
+
   bool hasActiveVectorLength() const { return false; }
 
 protected:

diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -1056,6 +1056,10 @@ unsigned TargetTransformInfo::getGISelRematGlobalCost() const {
   return TTIImpl->getGISelRematGlobalCost();
 }
 
+bool TargetTransformInfo::supportsScalableVectors() const {
+  return TTIImpl->supportsScalableVectors();
+}
+
 int TargetTransformInfo::getInstructionLatency(const Instruction *I) const {
   return TTIImpl->getInstructionLatency(I);
 }

diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
@@ -228,6 +228,8 @@ class AArch64TTIImpl : public BasicTTIImplBase<AArch64TTIImpl> {
     return 2;
   }
 
+  bool supportsScalableVectors() const { return ST->hasSVE(); }
+
   bool useReductionIntrinsic(unsigned Opcode, Type *Ty,
                              TTI::ReductionFlags Flags) const;