[Alignment] Replace commonAlignment with std::min

`commonAlignment` is a shortcut to pick the smallest of two `Align`
objects. As-is it doesn't bring much value compared to `std::min`.

Differential Revision: https://reviews.llvm.org/D128345

Author: gchatelet

llvm/include/llvm/Support/Alignment.h

@@ -208,10 +208,6 @@ inline uint64_t offsetToAlignedAddr(const void *Addr, Align Alignment) {
 /// Returns the log2 of the alignment.
 inline unsigned Log2(Align A) { return A.ShiftValue; }
 
-/// Returns the alignment that satisfies both alignments.
-/// Same semantic as MinAlign.
-inline Align commonAlignment(Align A, Align B) { return std::min(A, B); }
-
 /// Returns the alignment that satisfies both alignments.
 /// Same semantic as MinAlign.
 inline Align commonAlignment(Align A, uint64_t Offset) {

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

@@ -7627,7 +7627,7 @@ LegalizerHelper::lowerMemcpy(MachineInstr &MI, Register Dst, Register Src,
 
   bool DstAlignCanChange = false;
   MachineFrameInfo &MFI = MF.getFrameInfo();
-  Align Alignment = commonAlignment(DstAlign, SrcAlign);
+  Align Alignment = std::min(DstAlign, SrcAlign);
 
   MachineInstr *FIDef = getOpcodeDef(TargetOpcode::G_FRAME_INDEX, Dst, MRI);
   if (FIDef && !MFI.isFixedObjectIndex(FIDef->getOperand(1).getIndex()))
@@ -7735,7 +7735,7 @@ LegalizerHelper::lowerMemmove(MachineInstr &MI, Register Dst, Register Src,
   bool DstAlignCanChange = false;
   MachineFrameInfo &MFI = MF.getFrameInfo();
   bool OptSize = shouldLowerMemFuncForSize(MF);
-  Align Alignment = commonAlignment(DstAlign, SrcAlign);
+  Align Alignment = std::min(DstAlign, SrcAlign);
 
   MachineInstr *FIDef = getOpcodeDef(TargetOpcode::G_FRAME_INDEX, Dst, MRI);
   if (FIDef && !MFI.isFixedObjectIndex(FIDef->getOperand(1).getIndex()))

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -5861,7 +5861,7 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
     // @llvm.memcpy defines 0 and 1 to both mean no alignment.
     Align DstAlign = MCI.getDestAlign().valueOrOne();
     Align SrcAlign = MCI.getSourceAlign().valueOrOne();
-    Align Alignment = commonAlignment(DstAlign, SrcAlign);
+    Align Alignment = std::min(DstAlign, SrcAlign);
     bool isVol = MCI.isVolatile();
     bool isTC = I.isTailCall() && isInTailCallPosition(I, DAG.getTarget());
     // FIXME: Support passing different dest/src alignments to the memcpy DAG
@@ -5884,7 +5884,7 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
     // @llvm.memcpy.inline defines 0 and 1 to both mean no alignment.
     Align DstAlign = MCI.getDestAlign().valueOrOne();
     Align SrcAlign = MCI.getSourceAlign().valueOrOne();
-    Align Alignment = commonAlignment(DstAlign, SrcAlign);
+    Align Alignment = std::min(DstAlign, SrcAlign);
     bool isVol = MCI.isVolatile();
     bool isTC = I.isTailCall() && isInTailCallPosition(I, DAG.getTarget());
     // FIXME: Support passing different dest/src alignments to the memcpy DAG
@@ -5939,7 +5939,7 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
     // @llvm.memmove defines 0 and 1 to both mean no alignment.
     Align DstAlign = MMI.getDestAlign().valueOrOne();
     Align SrcAlign = MMI.getSourceAlign().valueOrOne();
-    Align Alignment = commonAlignment(DstAlign, SrcAlign);
+    Align Alignment = std::min(DstAlign, SrcAlign);
     bool isVol = MMI.isVolatile();
     bool isTC = I.isTailCall() && isInTailCallPosition(I, DAG.getTarget());
     // FIXME: Support passing different dest/src alignments to the memmove DAG

llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp

@@ -773,7 +773,7 @@ bool MemCpyOptPass::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
           LI, SI, SI->getPointerOperand()->stripPointerCasts(),
           LI->getPointerOperand()->stripPointerCasts(),
           DL.getTypeStoreSize(SI->getOperand(0)->getType()),
-          commonAlignment(SI->getAlign(), LI->getAlign()), GetCall);
+          std::min(SI->getAlign(), LI->getAlign()), GetCall);
       if (changed) {
         eraseInstruction(SI);
         eraseInstruction(LI);

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -3558,7 +3558,7 @@ static LoadsState canVectorizeLoads(ArrayRef<Value *> VL, const Value *VL0,
       Align CommonAlignment = cast<LoadInst>(VL0)->getAlign();
       for (Value *V : VL)
         CommonAlignment =
-            commonAlignment(CommonAlignment, cast<LoadInst>(V)->getAlign());
+            std::min(CommonAlignment, cast<LoadInst>(V)->getAlign());
       auto *VecTy = FixedVectorType::get(ScalarTy, VL.size());
       if (TTI.isLegalMaskedGather(VecTy, CommonAlignment) &&
           !TTI.forceScalarizeMaskedGather(VecTy, CommonAlignment))
@@ -6440,7 +6440,7 @@ InstructionCost BoUpSLP::getEntryCost(const TreeEntry *E,
         Align CommonAlignment = Alignment;
         for (Value *V : VL)
           CommonAlignment =
-              commonAlignment(CommonAlignment, cast<LoadInst>(V)->getAlign());
+              std::min(CommonAlignment, cast<LoadInst>(V)->getAlign());
         VecLdCost = TTI->getGatherScatterOpCost(
             Instruction::Load, VecTy, cast<LoadInst>(VL0)->getPointerOperand(),
             /*VariableMask=*/false, CommonAlignment, CostKind, VL0);
@@ -8157,7 +8157,7 @@ Value *BoUpSLP::vectorizeTree(TreeEntry *E) {
         Align CommonAlignment = LI->getAlign();
         for (Value *V : E->Scalars)
           CommonAlignment =
-              commonAlignment(CommonAlignment, cast<LoadInst>(V)->getAlign());
+              std::min(CommonAlignment, cast<LoadInst>(V)->getAlign());
         NewLI = Builder.CreateMaskedGather(VecTy, VecPtr, CommonAlignment);
       }
       Value *V = propagateMetadata(NewLI, E->Scalars);

llvm/unittests/Support/AlignmentTest.cpp

@@ -113,21 +113,6 @@ TEST(AlignmentTest, Log2) {
   }
 }
 
-TEST(AlignmentTest, MinAlign) {
-  struct {
-    uint64_t A;
-    uint64_t B;
-    uint64_t MinAlign;
-  } kTests[] = {
-      {1, 2, 1},
-      {8, 4, 4},
-  };
-  for (const auto &T : kTests) {
-    EXPECT_EQ(MinAlign(T.A, T.B), T.MinAlign);
-    EXPECT_EQ(commonAlignment(Align(T.A), Align(T.B)), T.MinAlign);
-  }
-}
-
 TEST(AlignmentTest, Encode_Decode) {
   for (uint64_t Value : getValidAlignments()) {
     {