[SVE] Replace / operator in TypeSize/ElementCount with divideCoefficientBy

After some recent upstream discussion we decided that it was best
to avoid having the / operator for both ElementCount and TypeSize,
since this could give the impression that these classes can be used
in the same way as basic integer integer types. However, division
for scalable types is a bit odd because we are only dividing the
minimum quantity by a value, as opposed to something like:

  (MinSize * Vscale) / SomeValue

This is why when performing division it's important the caller
first establishes whether the operation makes sense, perhaps by
calling isKnownMultipleOf() prior to division. The caller must now
explictly call divideCoefficientBy() on the class to perform the
operation.

Differential Revision: https://reviews.llvm.org/D87700

1 files changed, 6 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index 26ec3f1..84b596b 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -831,9 +831,7 @@ TargetLoweringBase::getTypeConversion(LLVMContext &Context, EVT VT) const {
            "Promote may not follow Expand or Promote");
 
     if (LA == TypeSplitVector)
-      return LegalizeKind(LA,
-                          EVT::getVectorVT(Context, SVT.getVectorElementType(),
-                                           SVT.getVectorElementCount() / 2));
+      return LegalizeKind(LA, EVT(SVT).getHalfNumVectorElementsVT(Context));
     if (LA == TypeScalarizeVector)
       return LegalizeKind(LA, SVT.getVectorElementType());
     return LegalizeKind(LA, NVT);
@@ -889,7 +887,7 @@ TargetLoweringBase::getTypeConversion(LLVMContext &Context, EVT VT) const {
     //  <4 x i140> -> <2 x i140>
     if (LK.first == TypeExpandInteger)
       return LegalizeKind(TypeSplitVector,
-                          EVT::getVectorVT(Context, EltVT, NumElts / 2));
+                          VT.getHalfNumVectorElementsVT(Context));
 
     // Promote the integer element types until a legal vector type is found
     // or until the element integer type is too big. If a legal type was not
@@ -949,7 +947,8 @@ TargetLoweringBase::getTypeConversion(LLVMContext &Context, EVT VT) const {
   }
 
   // Vectors with illegal element types are expanded.
-  EVT NVT = EVT::getVectorVT(Context, EltVT, VT.getVectorElementCount() / 2);
+  EVT NVT = EVT::getVectorVT(Context, EltVT,
+                             VT.getVectorElementCount().divideCoefficientBy(2));
   return LegalizeKind(TypeSplitVector, NVT);
 }
 
@@ -982,7 +981,7 @@ static unsigned getVectorTypeBreakdownMVT(MVT VT, MVT &IntermediateVT,
   // scalar.
   while (EC.getKnownMinValue() > 1 &&
          !TLI->isTypeLegal(MVT::getVectorVT(EltTy, EC))) {
-    EC /= 2;
+    EC = EC.divideCoefficientBy(2);
     NumVectorRegs <<= 1;
   }
 
@@ -1482,7 +1481,7 @@ unsigned TargetLoweringBase::getVectorTypeBreakdown(LLVMContext &Context, EVT VT
   // end with a scalar if the target doesn't support vectors.
   while (EltCnt.getKnownMinValue() > 1 &&
          !isTypeLegal(EVT::getVectorVT(Context, EltTy, EltCnt))) {
-    EltCnt /= 2;
+    EltCnt = EltCnt.divideCoefficientBy(2);
     NumVectorRegs <<= 1;
   }