[llvm] AMDGPU/PromoteAlloca: Refactor into analysis / commit phases (PR #170512)

[via llvm-commits]

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@@ -442,69 +543,58 @@ static Value *GEPToVectorIndex(GetElementPtrInst *GEP, AllocaInst *Alloca,
 
   int64_t VecElemSize = DL.getTypeAllocSize(VecElemTy);
   if (VarOffsets.size() > 1)
-    return nullptr;
+    return {};
 
   APInt IndexQuot;
   int64_t Rem;
   APInt::sdivrem(ConstOffset, VecElemSize, IndexQuot, Rem);
   if (Rem != 0)
-    return nullptr;
-  if (VarOffsets.size() == 0)
-    return ConstantInt::get(Ctx, IndexQuot);
+    return {};
+
+  GEPToVectorIndex Result;
 
-  IRBuilder<> Builder(GEP);
+  if (!ConstOffset.isZero())
+    Result.ConstIndex = ConstantInt::get(Ctx, IndexQuot.sextOrTrunc(BW));
+
+  if (VarOffsets.empty())
+    return Result;
 
   const auto &VarOffset = VarOffsets.front();
   APInt OffsetQuot;
   APInt::sdivrem(VarOffset.second, VecElemSize, OffsetQuot, Rem);
   if (Rem != 0 || OffsetQuot.isZero())
-    return nullptr;
-
-  Value *Offset = VarOffset.first;
-  if (!isa<IntegerType>(Offset->getType()))
-    return nullptr;
+    return {};
 
-  Offset = Builder.CreateSExtOrTrunc(Offset, Builder.getIntNTy(BW));
-  if (Offset != VarOffset.first)
-    NewInsts.push_back(cast<Instruction>(Offset));
+  Result.VarIndex = VarOffset.first;
+  auto *OffsetType = dyn_cast<IntegerType>(Result.VarIndex->getType());
+  if (!OffsetType)
+    return {};
 
   if (!OffsetQuot.isOne()) {
-    ConstantInt *ConstMul = ConstantInt::get(Ctx, OffsetQuot.sextOrTrunc(BW));
-    Offset = Builder.CreateMul(Offset, ConstMul);
-    if (Instruction *NewInst = dyn_cast<Instruction>(Offset))
-      NewInsts.push_back(NewInst);
+    Result.VarMul = ConstantInt::get(Ctx, OffsetQuot.sextOrTrunc(BW));
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ruiling wrote:

No parenthesis.

https://github.com/llvm/llvm-project/pull/170512