[SROA] NFC: Extract code to checkVectorTypesForPromotion

Change-Id: Ib6f237cc791a097f8f2411bc1d6502f11d4a748e

Author: jrbyrnes

llvm/lib/Transforms/Scalar/SROA.cpp

@@ -2138,8 +2138,9 @@ static bool isVectorPromotionViableForSlice(Partition &P, const Slice &S,
 
 /// Test whether a vector type is viable for promotion.
 ///
-/// This implements the necessary checking for \c isVectorPromotionViable over
-/// all slices of the alloca for the given VectorType.
+/// This implements the necessary checking for \c checkVectorTypesForPromotion
+/// (and thus isVectorPromotionViable) over all slices of the alloca for the
+/// given VectorType.
 static bool checkVectorTypeForPromotion(Partition &P, VectorType *VTy,
                                         const DataLayout &DL) {
   uint64_t ElementSize =
@@ -2164,6 +2165,98 @@ static bool checkVectorTypeForPromotion(Partition &P, VectorType *VTy,
   return true;
 }
 
+/// Test whether any vector type in \p CandidateTys is viable for promotion.
+///
+/// This implements the necessary checking for \c isVectorPromotionViable over
+/// all slices of the alloca for the given VectorType.
+static VectorType *
+checkVectorTypesForPromotion(Partition &P, const DataLayout &DL,
+                             SmallVectorImpl<VectorType *> &CandidateTys,
+                             bool HaveCommonEltTy, Type *CommonEltTy,
+                             bool HaveVecPtrTy, bool HaveCommonVecPtrTy,
+                             VectorType *CommonVecPtrTy) {
+  // If we didn't find a vector type, nothing to do here.
+  if (CandidateTys.empty())
+    return nullptr;
+
+  // Pointer-ness is sticky, if we had a vector-of-pointers candidate type,
+  // then we should choose it, not some other alternative.
+  // But, we can't perform a no-op pointer address space change via bitcast,
+  // so if we didn't have a common pointer element type, bail.
+  if (HaveVecPtrTy && !HaveCommonVecPtrTy)
+    return nullptr;
+
+  // Try to pick the "best" element type out of the choices.
+  if (!HaveCommonEltTy && HaveVecPtrTy) {
+    // If there was a pointer element type, there's really only one choice.
+    CandidateTys.clear();
+    CandidateTys.push_back(CommonVecPtrTy);
+  } else if (!HaveCommonEltTy && !HaveVecPtrTy) {
+    // Integer-ify vector types.
+    for (VectorType *&VTy : CandidateTys) {
+      if (!VTy->getElementType()->isIntegerTy())
+        VTy = cast<VectorType>(VTy->getWithNewType(IntegerType::getIntNTy(
+            VTy->getContext(), VTy->getScalarSizeInBits())));
+    }
+
+    // Rank the remaining candidate vector types. This is easy because we know
+    // they're all integer vectors. We sort by ascending number of elements.
+    auto RankVectorTypesComp = [&DL](VectorType *RHSTy, VectorType *LHSTy) {
+      (void)DL;
+      assert(DL.getTypeSizeInBits(RHSTy).getFixedValue() ==
+                 DL.getTypeSizeInBits(LHSTy).getFixedValue() &&
+             "Cannot have vector types of different sizes!");
+      assert(RHSTy->getElementType()->isIntegerTy() &&
+             "All non-integer types eliminated!");
+      assert(LHSTy->getElementType()->isIntegerTy() &&
+             "All non-integer types eliminated!");
+      return cast<FixedVectorType>(RHSTy)->getNumElements() <
+             cast<FixedVectorType>(LHSTy)->getNumElements();
+    };
+    auto RankVectorTypesEq = [&DL](VectorType *RHSTy, VectorType *LHSTy) {
+      (void)DL;
+      assert(DL.getTypeSizeInBits(RHSTy).getFixedValue() ==
+                 DL.getTypeSizeInBits(LHSTy).getFixedValue() &&
+             "Cannot have vector types of different sizes!");
+      assert(RHSTy->getElementType()->isIntegerTy() &&
+             "All non-integer types eliminated!");
+      assert(LHSTy->getElementType()->isIntegerTy() &&
+             "All non-integer types eliminated!");
+      return cast<FixedVectorType>(RHSTy)->getNumElements() ==
+             cast<FixedVectorType>(LHSTy)->getNumElements();
+    };
+    llvm::sort(CandidateTys, RankVectorTypesComp);
+    CandidateTys.erase(std::unique(CandidateTys.begin(), CandidateTys.end(),
+                                   RankVectorTypesEq),
+                       CandidateTys.end());
+  } else {
+// The only way to have the same element type in every vector type is to
+// have the same vector type. Check that and remove all but one.
+#ifndef NDEBUG
+    for (VectorType *VTy : CandidateTys) {
+      assert(VTy->getElementType() == CommonEltTy &&
+             "Unaccounted for element type!");
+      assert(VTy == CandidateTys[0] &&
+             "Different vector types with the same element type!");
+    }
+#endif
+    CandidateTys.resize(1);
+  }
+
+  // FIXME: hack. Do we have a named constant for this?
+  // SDAG SDNode can't have more than 65535 operands.
+  llvm::erase_if(CandidateTys, [](VectorType *VTy) {
+    return cast<FixedVectorType>(VTy)->getNumElements() >
+           std::numeric_limits<unsigned short>::max();
+  });
+
+  for (VectorType *VTy : CandidateTys)
+    if (checkVectorTypeForPromotion(P, VTy, DL))
+      return VTy;
+
+  return nullptr;
+}
+
 /// Test whether the given alloca partitioning and range of slices can be
 /// promoted to a vector.
 ///
@@ -2211,6 +2304,7 @@ static VectorType *isVectorPromotionViable(Partition &P, const DataLayout &DL) {
       }
     }
   };
+
   // Put load and store types into a set for de-duplication.
   for (const Slice &S : P) {
     Type *Ty;
@@ -2246,86 +2340,9 @@ static VectorType *isVectorPromotionViable(Partition &P, const DataLayout &DL) {
     }
   }
 
-  // If we didn't find a vector type, nothing to do here.
-  if (CandidateTys.empty())
-    return nullptr;
-
-  // Pointer-ness is sticky, if we had a vector-of-pointers candidate type,
-  // then we should choose it, not some other alternative.
-  // But, we can't perform a no-op pointer address space change via bitcast,
-  // so if we didn't have a common pointer element type, bail.
-  if (HaveVecPtrTy && !HaveCommonVecPtrTy)
-    return nullptr;
-
-  // Try to pick the "best" element type out of the choices.
-  if (!HaveCommonEltTy && HaveVecPtrTy) {
-    // If there was a pointer element type, there's really only one choice.
-    CandidateTys.clear();
-    CandidateTys.push_back(CommonVecPtrTy);
-  } else if (!HaveCommonEltTy && !HaveVecPtrTy) {
-    // Integer-ify vector types.
-    for (VectorType *&VTy : CandidateTys) {
-      if (!VTy->getElementType()->isIntegerTy())
-        VTy = cast<VectorType>(VTy->getWithNewType(IntegerType::getIntNTy(
-            VTy->getContext(), VTy->getScalarSizeInBits())));
-    }
-
-    // Rank the remaining candidate vector types. This is easy because we know
-    // they're all integer vectors. We sort by ascending number of elements.
-    auto RankVectorTypesComp = [&DL](VectorType *RHSTy, VectorType *LHSTy) {
-      (void)DL;
-      assert(DL.getTypeSizeInBits(RHSTy).getFixedValue() ==
-                 DL.getTypeSizeInBits(LHSTy).getFixedValue() &&
-             "Cannot have vector types of different sizes!");
-      assert(RHSTy->getElementType()->isIntegerTy() &&
-             "All non-integer types eliminated!");
-      assert(LHSTy->getElementType()->isIntegerTy() &&
-             "All non-integer types eliminated!");
-      return cast<FixedVectorType>(RHSTy)->getNumElements() <
-             cast<FixedVectorType>(LHSTy)->getNumElements();
-    };
-    auto RankVectorTypesEq = [&DL](VectorType *RHSTy, VectorType *LHSTy) {
-      (void)DL;
-      assert(DL.getTypeSizeInBits(RHSTy).getFixedValue() ==
-                 DL.getTypeSizeInBits(LHSTy).getFixedValue() &&
-             "Cannot have vector types of different sizes!");
-      assert(RHSTy->getElementType()->isIntegerTy() &&
-             "All non-integer types eliminated!");
-      assert(LHSTy->getElementType()->isIntegerTy() &&
-             "All non-integer types eliminated!");
-      return cast<FixedVectorType>(RHSTy)->getNumElements() ==
-             cast<FixedVectorType>(LHSTy)->getNumElements();
-    };
-    llvm::sort(CandidateTys, RankVectorTypesComp);
-    CandidateTys.erase(std::unique(CandidateTys.begin(), CandidateTys.end(),
-                                   RankVectorTypesEq),
-                       CandidateTys.end());
-  } else {
-// The only way to have the same element type in every vector type is to
-// have the same vector type. Check that and remove all but one.
-#ifndef NDEBUG
-    for (VectorType *VTy : CandidateTys) {
-      assert(VTy->getElementType() == CommonEltTy &&
-             "Unaccounted for element type!");
-      assert(VTy == CandidateTys[0] &&
-             "Different vector types with the same element type!");
-    }
-#endif
-    CandidateTys.resize(1);
-  }
-
-  // FIXME: hack. Do we have a named constant for this?
-  // SDAG SDNode can't have more than 65535 operands.
-  llvm::erase_if(CandidateTys, [](VectorType *VTy) {
-    return cast<FixedVectorType>(VTy)->getNumElements() >
-           std::numeric_limits<unsigned short>::max();
-  });
-
-  for (VectorType *VTy : CandidateTys)
-    if (checkVectorTypeForPromotion(P, VTy, DL))
-      return VTy;
-
-  return nullptr;
+  return checkVectorTypesForPromotion(P, DL, CandidateTys, HaveCommonEltTy,
+                                      CommonEltTy, HaveVecPtrTy,
+                                      HaveCommonVecPtrTy, CommonVecPtrTy);
 }
 
 /// Test whether a slice of an alloca is valid for integer widening.