[SROA] Yet another slight refactoring that simplifies an API in the

rewriting logic: don't pass custom offsets for the adjusted pointer to
the new alloca.

We always passed NewBeginOffset here. Sometimes we spelled it
BeginOffset, but only when they were in fact equal. Whats worse, the API
is set up so that you can't reasonably call it with anything else -- it
assumes that you're passing it an offset relative to the *original*
alloca that happens to fall within the new one. That's the whole point
of NewBeginOffset, it's the clamped beginning offset.

No functionality changed.

llvm-svn: 202231

1 files changed, 19 insertions, 20 deletions

diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
index ab815fe0600..85d27982683 100644
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -2102,9 +2102,12 @@ private:
     llvm_unreachable("No rewrite rule for this instruction!");
   }
 
-  Value *getAdjustedAllocaPtr(IRBuilderTy &IRB, uint64_t Offset,
-                              Type *PointerTy) {
-    assert(Offset >= NewAllocaBeginOffset);
+  Value *getNewAllocaSlicePtr(IRBuilderTy &IRB, Type *PointerTy) {
+    // Note that the offset computation can use BeginOffset or NewBeginOffset
+    // interchangeably for unsplit slices.
+    assert(IsSplit || BeginOffset == NewBeginOffset);
+    uint64_t Offset = NewBeginOffset - NewAllocaBeginOffset;
+
 #ifndef NDEBUG
     StringRef OldName = OldPtr->getName();
     // Skip through the last '.sroa.' component of the name.
@@ -2125,9 +2128,9 @@ private:
     // Strip any SROA suffixes as well.
     OldName = OldName.substr(0, OldName.find(".sroa_"));
 #endif
-    return getAdjustedPtr(IRB, DL, &NewAI, APInt(DL.getPointerSizeInBits(),
-                                                 Offset - NewAllocaBeginOffset),
-                          PointerTy,
+
+    return getAdjustedPtr(IRB, DL, &NewAI,
+                          APInt(DL.getPointerSizeInBits(), Offset), PointerTy,
 #ifndef NDEBUG
                           Twine(OldName) + "."
 #else
@@ -2206,7 +2209,7 @@ private:
                                 LI.isVolatile(), LI.getName());
     } else {
       Type *LTy = TargetTy->getPointerTo();
-      V = IRB.CreateAlignedLoad(getAdjustedAllocaPtr(IRB, NewBeginOffset, LTy),
+      V = IRB.CreateAlignedLoad(getNewAllocaSlicePtr(IRB, LTy),
                                 getSliceAlign(TargetTy), LI.isVolatile(),
                                 LI.getName());
       IsPtrAdjusted = true;
@@ -2329,8 +2332,7 @@ private:
       NewSI = IRB.CreateAlignedStore(V, &NewAI, NewAI.getAlignment(),
                                      SI.isVolatile());
     } else {
-      Value *NewPtr = getAdjustedAllocaPtr(IRB, NewBeginOffset,
-                                           V->getType()->getPointerTo());
+      Value *NewPtr = getNewAllocaSlicePtr(IRB, V->getType()->getPointerTo());
       NewSI = IRB.CreateAlignedStore(V, NewPtr, getSliceAlign(V->getType()),
                                      SI.isVolatile());
     }
@@ -2385,7 +2387,7 @@ private:
     if (!isa<Constant>(II.getLength())) {
       assert(!IsSplit);
       assert(NewBeginOffset == BeginOffset);
-      II.setDest(getAdjustedAllocaPtr(IRB, NewBeginOffset, OldPtr->getType()));
+      II.setDest(getNewAllocaSlicePtr(IRB, OldPtr->getType()));
       Type *CstTy = II.getAlignmentCst()->getType();
       II.setAlignment(ConstantInt::get(CstTy, getSliceAlign()));
 
@@ -2410,8 +2412,8 @@ private:
       Type *SizeTy = II.getLength()->getType();
       Constant *Size = ConstantInt::get(SizeTy, NewEndOffset - NewBeginOffset);
       CallInst *New = IRB.CreateMemSet(
-          getAdjustedAllocaPtr(IRB, NewBeginOffset, OldPtr->getType()),
-          II.getValue(), Size, getSliceAlign(), II.isVolatile());
+          getNewAllocaSlicePtr(IRB, OldPtr->getType()), II.getValue(), Size,
+          getSliceAlign(), II.isVolatile());
       (void)New;
       DEBUG(dbgs() << "          to: " << *New << "\n");
       return false;
@@ -2509,8 +2511,7 @@ private:
     // memcpy, and so simply updating the pointers is the necessary for us to
     // update both source and dest of a single call.
     if (!IsSplittable) {
-      Value *AdjustedPtr =
-          getAdjustedAllocaPtr(IRB, BeginOffset, OldPtr->getType());
+      Value *AdjustedPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
       if (IsDest)
         II.setDest(AdjustedPtr);
       else
@@ -2570,8 +2571,7 @@ private:
       OtherPtr = getAdjustedPtr(IRB, DL, OtherPtr, RelOffset, OtherPtrTy,
                                 OtherPtr->getName() + ".");
 
-      Value *OurPtr =
-          getAdjustedAllocaPtr(IRB, NewBeginOffset, OldPtr->getType());
+      Value *OurPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
       Type *SizeTy = II.getLength()->getType();
       Constant *Size = ConstantInt::get(SizeTy, NewEndOffset - NewBeginOffset);
 
@@ -2664,7 +2664,7 @@ private:
     ConstantInt *Size
       = ConstantInt::get(cast<IntegerType>(II.getArgOperand(0)->getType()),
                          NewEndOffset - NewBeginOffset);
-    Value *Ptr = getAdjustedAllocaPtr(IRB, NewBeginOffset, OldPtr->getType());
+    Value *Ptr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
     Value *New;
     if (II.getIntrinsicID() == Intrinsic::lifetime_start)
       New = IRB.CreateLifetimeStart(Ptr, Size);
@@ -2689,8 +2689,7 @@ private:
     PtrBuilder.SetInsertPoint(OldPtr);
     PtrBuilder.SetCurrentDebugLocation(OldPtr->getDebugLoc());
 
-    Value *NewPtr =
-        getAdjustedAllocaPtr(PtrBuilder, BeginOffset, OldPtr->getType());
+    Value *NewPtr = getNewAllocaSlicePtr(PtrBuilder, OldPtr->getType());
     // Replace the operands which were using the old pointer.
     std::replace(PN.op_begin(), PN.op_end(), cast<Value>(OldPtr), NewPtr);
 
@@ -2711,7 +2710,7 @@ private:
     assert(BeginOffset >= NewAllocaBeginOffset && "Selects are unsplittable");
     assert(EndOffset <= NewAllocaEndOffset && "Selects are unsplittable");
 
-    Value *NewPtr = getAdjustedAllocaPtr(IRB, BeginOffset, OldPtr->getType());
+    Value *NewPtr = getNewAllocaSlicePtr(IRB, OldPtr->getType());
     // Replace the operands which were using the old pointer.
     if (SI.getOperand(1) == OldPtr)
       SI.setOperand(1, NewPtr);