r331065 | dim | 2018-03-16 18:50:44 +0100 (Fri, 16 Mar 2018) | 17 lines

Pull in r327638 from upstream llvm trunk (by Matthew Simpson):

  [ConstantFolding, InstSimplify] Handle more vector GEPs

  This patch addresses some additional cases where the compiler crashes
  upon encountering vector GEPs. This should fix PR36116.

  Differential Revision: https://reviews.llvm.org/D44219
  Reference: https://bugs.llvm.org/show_bug.cgi?id=36116

This fixes an assertion when building the emulators/snes9x port.

Reported by:	jbeich
PR:		225471
MFC after:	3 months
X-MFC-With:	r327952

Index: lib/Analysis/InstructionSimplify.cpp
===================================================================
--- lib/Analysis/InstructionSimplify.cpp	(revision 331064)
+++ lib/Analysis/InstructionSimplify.cpp	(revision 331065)
@@ -3697,7 +3697,7 @@ static Value *SimplifyGEPInst(Type *SrcTy, ArrayRe
 
   if (Ops.size() == 2) {
     // getelementptr P, 0 -> P.
-    if (match(Ops[1], m_Zero()))
+    if (match(Ops[1], m_Zero()) && Ops[0]->getType() == GEPTy)
       return Ops[0];
 
     Type *Ty = SrcTy;
@@ -3706,7 +3706,7 @@ static Value *SimplifyGEPInst(Type *SrcTy, ArrayRe
       uint64_t C;
       uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
       // getelementptr P, N -> P if P points to a type of zero size.
-      if (TyAllocSize == 0)
+      if (TyAllocSize == 0 && Ops[0]->getType() == GEPTy)
         return Ops[0];
 
       // The following transforms are only safe if the ptrtoint cast
Index: lib/IR/ConstantFold.cpp
===================================================================
--- lib/IR/ConstantFold.cpp	(revision 331064)
+++ lib/IR/ConstantFold.cpp	(revision 331065)
@@ -2018,8 +2018,16 @@ static bool isInBoundsIndices(ArrayRef<IndexTy> Id
 
   // If the first index is one and all the rest are zero, it's in bounds,
   // by the one-past-the-end rule.
-  if (!cast<ConstantInt>(Idxs[0])->isOne())
-    return false;
+  if (auto *CI = dyn_cast<ConstantInt>(Idxs[0])) {
+    if (!CI->isOne())
+      return false;
+  } else {
+    auto *CV = cast<ConstantDataVector>(Idxs[0]);
+    CI = dyn_cast_or_null<ConstantInt>(CV->getSplatValue());
+    if (!CI || !CI->isOne())
+      return false;
+  }
+
   for (unsigned i = 1, e = Idxs.size(); i != e; ++i)
     if (!cast<Constant>(Idxs[i])->isNullValue())
       return false;
@@ -2049,15 +2057,18 @@ Constant *llvm::ConstantFoldGetElementPtr(Type *Po
                                           ArrayRef<Value *> Idxs) {
   if (Idxs.empty()) return C;
 
-  if (isa<UndefValue>(C)) {
-    Type *GEPTy = GetElementPtrInst::getGEPReturnType(
-        C, makeArrayRef((Value * const *)Idxs.data(), Idxs.size()));
+  Type *GEPTy = GetElementPtrInst::getGEPReturnType(
+      C, makeArrayRef((Value *const *)Idxs.data(), Idxs.size()));
+
+  if (isa<UndefValue>(C))
     return UndefValue::get(GEPTy);
-  }
 
   Constant *Idx0 = cast<Constant>(Idxs[0]);
   if (Idxs.size() == 1 && (Idx0->isNullValue() || isa<UndefValue>(Idx0)))
-    return C;
+    return GEPTy->isVectorTy() && !C->getType()->isVectorTy()
+               ? ConstantVector::getSplat(
+                     cast<VectorType>(GEPTy)->getNumElements(), C)
+               : C;
 
   if (C->isNullValue()) {
     bool isNull = true;