[SVE] Eliminate calls to default-false VectorType::get() from Analysis

[fpetrogalli]

LGTM! Thank you!

[ctetreau]

rebase

llvm/lib/Analysis/ConstantFolding.cpp

if (auto *VTy = dyn_cast<VectorType>(C->getType())) {
     if (isa<IntegerType>(DestTy) || DestTy->isFloatingPointTy()) {
       unsigned NumSrcElts = VTy->getNumElements();
       Type *SrcEltTy = VTy->getElementType();
 
       // If the vector is a vector of floating point, convert it to vector of int
       // to simplify things.
       if (SrcEltTy->isFloatingPointTy()) {
         unsigned FPWidth = SrcEltTy->getPrimitiveSizeInBits();
-        Type *SrcIVTy =
-          VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumSrcElts);
+        auto *SrcIVTy = FixedVectorType::get(
+            IntegerType::get(C->getContext(), FPWidth), NumSrcElts);
         // Ask IR to do the conversion now that #elts line up.
         C = ConstantExpr::getBitCast(C, SrcIVTy);
       }
 
       APInt Result(DL.getTypeSizeInBits(DestTy), 0);
       if (Constant *CE = foldConstVectorToAPInt(Result, DestTy, C,
                                                 SrcEltTy, NumSrcElts, DL))
         return CE;
Constant *FoldBitCast(Constant *C, Type *DestTy, const DataLayout &DL) {
   // and to (big endian):
   //    <4 x i32> <i32 0, i32 0, i32 0, i32 1>
 
   // First thing is first.  We only want to think about integer here, so if
   // we have something in FP form, recast it as integer.
   if (DstEltTy->isFloatingPointTy()) {
     // Fold to an vector of integers with same size as our FP type.
     unsigned FPWidth = DstEltTy->getPrimitiveSizeInBits();
-    Type *DestIVTy =
-      VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumDstElt);
+    auto *DestIVTy = FixedVectorType::get(
+        IntegerType::get(C->getContext(), FPWidth), NumDstElt);
     // Recursively handle this integer conversion, if possible.
     C = FoldBitCast(C, DestIVTy, DL);
 
     // Finally, IR can handle this now that #elts line up.
     return ConstantExpr::getBitCast(C, DestTy);
   }
 
   // Okay, we know the destination is integer, if the input is FP, convert
   // it to integer first.
   if (SrcEltTy->isFloatingPointTy()) {
     unsigned FPWidth = SrcEltTy->getPrimitiveSizeInBits();
-    Type *SrcIVTy =
-      VectorType::get(IntegerType::get(C->getContext(), FPWidth), NumSrcElt);
+    auto *SrcIVTy = FixedVectorType::get(
+        IntegerType::get(C->getContext(), FPWidth), NumSrcElt);
     // Ask IR to do the conversion now that #elts line up.
     C = ConstantExpr::getBitCast(C, SrcIVTy);
     // If IR wasn't able to fold it, bail out.
     if (!isa<ConstantVector>(C) &&  // FIXME: Remove ConstantVector.
         !isa<ConstantDataVector>(C))
       return C;
   }