[llvm] [LowerMemIntrinsics] Lower llvm.memmove to wide memory accesses (PR #100122)

[Fabian Ritter via llvm-commits]

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@@ -378,85 +382,229 @@ static void createMemMoveLoop(Instruction *InsertBefore, Value *SrcAddr,
   BasicBlock *OrigBB = InsertBefore->getParent();
   Function *F = OrigBB->getParent();
   const DataLayout &DL = F->getDataLayout();
-  // TODO: Use different element type if possible?
-  Type *EltTy = Type::getInt8Ty(F->getContext());
+  LLVMContext &Ctx = OrigBB->getContext();
+  unsigned SrcAS = cast<PointerType>(SrcAddr->getType())->getAddressSpace();
+  unsigned DstAS = cast<PointerType>(DstAddr->getType())->getAddressSpace();
+
+  Type *LoopOpType = TTI.getMemcpyLoopLoweringType(
+      Ctx, CopyLen, SrcAS, DstAS, SrcAlign.value(), DstAlign.value());
+  unsigned LoopOpSize = DL.getTypeStoreSize(LoopOpType);
+  Type *Int8Type = Type::getInt8Ty(Ctx);
+  bool LoopOpIsInt8 = LoopOpType == Int8Type;
+
+  // If the memory accesses are wider than one byte, residual loops with
+  // i8-accesses are required to move remaining bytes.
+  bool RequiresResidual = !LoopOpIsInt8;
+
+  // Calculate the loop trip count and remaining bytes to copy after the loop.
+  IntegerType *ILengthType = dyn_cast<IntegerType>(TypeOfCopyLen);
+  assert(ILengthType &&
+         "expected size argument to memcpy to be an integer type!");
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ritter-x2a wrote:

Addressed in dbe8d4c.

https://github.com/llvm/llvm-project/pull/100122