commit 957c40db6aebcbcdc4c80614649f917d93b73b4f
author Graham Hunter <graham.hunter@arm.com> Fri Jul 05 12:48:16 2019 +0000
committer Graham Hunter <graham.hunter@arm.com> Fri Jul 05 12:48:16 2019 +0000
tree f36d9a8b676d948d1bc64b46a5eacce2bc84ae53
parent 9dcfbbae76234818a748a7745c7ef8c89607f055

Scalable Vector IR Type with further LTO fixes

Reintroduces the scalable vector IR type from D32530, after it was reverted
a couple of times due to increasing chromium LTO build times. This latest
incarnation removes the walk over aggregate types from the verifier entirely,
in favor of rejecting scalable vectors in the isValidElementType methods in
ArrayType and StructType. This removes the 70% degradation observed with
the second repro tarball from PR42210.

Reviewers: thakis, hans, rengolin, sdesmalen

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D64079

llvm-svn: 365203

llvm/lib/IR/AsmWriter.cpp

diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
index a5adfd9..eb5760d 100644
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -620,7 +620,10 @@
   }
   case Type::VectorTyID: {
     VectorType *PTy = cast<VectorType>(Ty);
-    OS << "<" << PTy->getNumElements() << " x ";
+    OS << "<";
+    if (PTy->isScalable())
+      OS << "vscale x ";
+    OS << PTy->getNumElements() << " x ";
     print(PTy->getElementType(), OS);
     OS << '>';
     return;

llvm/lib/IR/LLVMContextImpl.h

diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index 4560617..78cf707 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -1334,7 +1334,7 @@
   unsigned NamedStructTypesUniqueID = 0;
 
   DenseMap<std::pair<Type *, uint64_t>, ArrayType*> ArrayTypes;
-  DenseMap<std::pair<Type *, unsigned>, VectorType*> VectorTypes;
+  DenseMap<std::pair<Type *, ElementCount>, VectorType*> VectorTypes;
   DenseMap<Type*, PointerType*> PointerTypes;  // Pointers in AddrSpace = 0
   DenseMap<std::pair<Type*, unsigned>, PointerType*> ASPointerTypes;
 

llvm/lib/IR/Type.cpp

diff --git a/llvm/lib/IR/Type.cpp b/llvm/lib/IR/Type.cpp
index 4016bb1..8ece7f2 100644
--- a/llvm/lib/IR/Type.cpp
+++ b/llvm/lib/IR/Type.cpp
@@ -504,6 +504,8 @@
 }
 
 bool StructType::isValidElementType(Type *ElemTy) {
+  if (auto *VTy = dyn_cast<VectorType>(ElemTy))
+    return !VTy->isScalable();
   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy() &&
          !ElemTy->isTokenTy();
@@ -590,6 +592,8 @@
 }
 
 bool ArrayType::isValidElementType(Type *ElemTy) {
+  if (auto *VTy = dyn_cast<VectorType>(ElemTy))
+    return !VTy->isScalable();
   return !ElemTy->isVoidTy() && !ElemTy->isLabelTy() &&
          !ElemTy->isMetadataTy() && !ElemTy->isFunctionTy() &&
          !ElemTy->isTokenTy();
@@ -599,21 +603,20 @@
 //                          VectorType Implementation
 //===----------------------------------------------------------------------===//
 
-VectorType::VectorType(Type *ElType, unsigned NumEl)
-  : SequentialType(VectorTyID, ElType, NumEl) {}
+VectorType::VectorType(Type *ElType, ElementCount EC)
+  : SequentialType(VectorTyID, ElType, EC.Min), Scalable(EC.Scalable) {}
 
-VectorType *VectorType::get(Type *ElementType, unsigned NumElements) {
-  assert(NumElements > 0 && "#Elements of a VectorType must be greater than 0");
+VectorType *VectorType::get(Type *ElementType, ElementCount EC) {
+  assert(EC.Min > 0 && "#Elements of a VectorType must be greater than 0");
   assert(isValidElementType(ElementType) && "Element type of a VectorType must "
                                             "be an integer, floating point, or "
                                             "pointer type.");
 
   LLVMContextImpl *pImpl = ElementType->getContext().pImpl;
   VectorType *&Entry = ElementType->getContext().pImpl
-    ->VectorTypes[std::make_pair(ElementType, NumElements)];
-
+                                 ->VectorTypes[std::make_pair(ElementType, EC)];
   if (!Entry)
-    Entry = new (pImpl->Alloc) VectorType(ElementType, NumElements);
+    Entry = new (pImpl->Alloc) VectorType(ElementType, EC);
   return Entry;
 }
 

llvm/lib/IR/Verifier.cpp

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 0ab421e..b046434 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -691,6 +691,13 @@
                       "DIGlobalVariableExpression");
   }
 
+  // Scalable vectors cannot be global variables, since we don't know
+  // the runtime size. If the global is a struct or an array containing
+  // scalable vectors, that will be caught by the isValidElementType methods
+  // in StructType or ArrayType instead.
+  if (auto *VTy = dyn_cast<VectorType>(GV.getValueType()))
+    Assert(!VTy->isScalable(), "Globals cannot contain scalable vectors", &GV);
+
   if (!GV.hasInitializer()) {
     visitGlobalValue(GV);
     return;