[llvm-commits] [llvm] r164003 - /llvm/trunk/lib/Transforms/Scalar/SROA.cpp

Chandler Carruth chandlerc at gmail.com
Sun Sep 16 12:39:50 PDT 2012 

Author: chandlerc
Date: Sun Sep 16 14:39:50 2012
New Revision: 164003

URL: http://llvm.org/viewvc/llvm-project?rev=164003&view=rev
Log:
Refactor the SROA visitors for partitioning an alloca and building
partition use lists a bit. No functionality changed.

These visitors are actually visiting a tuple of a Use and an offset into
the alloca. However, we use the InstVisitor to handle the dispatch over
the users, and so the Use and Offset are stored in class member
variables and set just before each call to visit(). This is fairly
awkward and makes the functions a bit harder to read, but its the only
real option we have until InstVisitor can be rewritten to use variadic
templates.

However, this pattern shouldn't be followed on the helper member
functions where there is no interface constraint from the visitor. We
already were passing the instruction as a normal parameter rather than
use the Use to get at it, start passing the offset as well. This will
become more important in subsequent patches as the offset will in some
cases change while visiting a single instruction.

Modified:
    llvm/trunk/lib/Transforms/Scalar/SROA.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/SROA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SROA.cpp?rev=164003&r1=164002&r2=164003&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SROA.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SROA.cpp Sun Sep 16 14:39:50 2012
@@ -490,7 +490,8 @@
     return false;
   }
 
-  void insertUse(Instruction &I, uint64_t Size, bool IsSplittable = false) {
+  void insertUse(Instruction &I, uint64_t Offset, uint64_t Size,
+                 bool IsSplittable = false) {
     uint64_t BeginOffset = Offset, EndOffset = Offset + Size;
 
     // Completely skip uses which start outside of the allocation.
@@ -524,7 +525,7 @@
     P.Partitions.push_back(New);
   }
 
-  bool handleLoadOrStore(Type *Ty, Instruction &I) {
+  bool handleLoadOrStore(Type *Ty, Instruction &I, uint64_t Offset) {
     uint64_t Size = TD.getTypeStoreSize(Ty);
 
     // If this memory access can be shown to *statically* extend outside the
@@ -544,7 +545,7 @@
       return true;
     }
 
-    insertUse(I, Size);
+    insertUse(I, Offset, Size);
     return true;
   }
 
@@ -563,21 +564,22 @@
   }
 
   bool visitLoadInst(LoadInst &LI) {
-    return handleLoadOrStore(LI.getType(), LI);
+    return handleLoadOrStore(LI.getType(), LI, Offset);
   }
 
   bool visitStoreInst(StoreInst &SI) {
     if (SI.getOperand(0) == *U)
       return markAsEscaping(SI);
 
-    return handleLoadOrStore(SI.getOperand(0)->getType(), SI);
+    return handleLoadOrStore(SI.getOperand(0)->getType(), SI, Offset);
   }
 
 
   bool visitMemSetInst(MemSetInst &II) {
     assert(II.getRawDest() == *U && "Pointer use is not the destination?");
     ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
-    insertUse(II, Length ? Length->getZExtValue() : AllocSize - Offset, Length);
+    uint64_t Size = Length ? Length->getZExtValue() : AllocSize - Offset;
+    insertUse(II, Offset, Size, Length);
     return true;
   }
 
@@ -602,7 +604,7 @@
       Offsets.DestEnd = Offset + Size;
     }
 
-    insertUse(II, Size, Offsets.IsSplittable);
+    insertUse(II, Offset, Size, Offsets.IsSplittable);
     unsigned NewIdx = P.Partitions.size() - 1;
 
     SmallDenseMap<Instruction *, unsigned>::const_iterator PMI;
@@ -630,7 +632,7 @@
         II.getIntrinsicID() == Intrinsic::lifetime_end) {
       ConstantInt *Length = cast<ConstantInt>(II.getArgOperand(0));
       uint64_t Size = std::min(AllocSize - Offset, Length->getLimitedValue());
-      insertUse(II, Size, true);
+      insertUse(II, Offset, Size, true);
       return true;
     }
 
@@ -684,7 +686,7 @@
     std::pair<uint64_t, bool> &PHIInfo = P.PHIOrSelectSizes[&PN];
     if (PHIInfo.first) {
       PHIInfo.second = true;
-      insertUse(PN, PHIInfo.first);
+      insertUse(PN, Offset, PHIInfo.first);
       return true;
     }
 
@@ -692,7 +694,7 @@
     if (Instruction *EscapingI = hasUnsafePHIOrSelectUse(&PN, PHIInfo.first))
       return markAsEscaping(*EscapingI);
 
-    insertUse(PN, PHIInfo.first);
+    insertUse(PN, Offset, PHIInfo.first);
     return true;
   }
 
@@ -710,7 +712,7 @@
     std::pair<uint64_t, bool> &SelectInfo = P.PHIOrSelectSizes[&SI];
     if (SelectInfo.first) {
       SelectInfo.second = true;
-      insertUse(SI, SelectInfo.first);
+      insertUse(SI, Offset, SelectInfo.first);
       return true;
     }
 
@@ -718,7 +720,7 @@
     if (Instruction *EscapingI = hasUnsafePHIOrSelectUse(&SI, SelectInfo.first))
       return markAsEscaping(*EscapingI);
 
-    insertUse(SI, SelectInfo.first);
+    insertUse(SI, Offset, SelectInfo.first);
     return true;
   }
 
@@ -772,7 +774,7 @@
       P.DeadUsers.push_back(&I);
   }
 
-  void insertUse(uint64_t Size, Instruction &User) {
+  void insertUse(Instruction &User, uint64_t Offset, uint64_t Size) {
     uint64_t BeginOffset = Offset, EndOffset = Offset + Size;
 
     // If the use extends outside of the allocation, record it as a dead use
@@ -800,7 +802,7 @@
     }
   }
 
-  void handleLoadOrStore(Type *Ty, Instruction &I) {
+  void handleLoadOrStore(Type *Ty, Instruction &I, uint64_t Offset) {
     uint64_t Size = TD.getTypeStoreSize(Ty);
 
     // If this memory access can be shown to *statically* extend outside the
@@ -810,7 +812,7 @@
     if (Offset >= AllocSize || Size > AllocSize || Offset + Size > AllocSize)
       return markAsDead(I);
 
-    insertUse(Size, I);
+    insertUse(I, Offset, Size);
   }
 
   void visitBitCastInst(BitCastInst &BC) {
@@ -832,21 +834,23 @@
   }
 
   void visitLoadInst(LoadInst &LI) {
-    handleLoadOrStore(LI.getType(), LI);
+    handleLoadOrStore(LI.getType(), LI, Offset);
   }
 
   void visitStoreInst(StoreInst &SI) {
-    handleLoadOrStore(SI.getOperand(0)->getType(), SI);
+    handleLoadOrStore(SI.getOperand(0)->getType(), SI, Offset);
   }
 
   void visitMemSetInst(MemSetInst &II) {
     ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
-    insertUse(Length ? Length->getZExtValue() : AllocSize - Offset, II);
+    uint64_t Size = Length ? Length->getZExtValue() : AllocSize - Offset;
+    insertUse(II, Offset, Size);
   }
 
   void visitMemTransferInst(MemTransferInst &II) {
     ConstantInt *Length = dyn_cast<ConstantInt>(II.getLength());
-    insertUse(Length ? Length->getZExtValue() : AllocSize - Offset, II);
+    uint64_t Size = Length ? Length->getZExtValue() : AllocSize - Offset;
+    insertUse(II, Offset, Size);
   }
 
   void visitIntrinsicInst(IntrinsicInst &II) {
@@ -854,10 +858,11 @@
            II.getIntrinsicID() == Intrinsic::lifetime_end);
 
     ConstantInt *Length = cast<ConstantInt>(II.getArgOperand(0));
-    insertUse(std::min(AllocSize - Offset, Length->getLimitedValue()), II);
+    insertUse(II, Offset,
+              std::min(AllocSize - Offset, Length->getLimitedValue()));
   }
 
-  void insertPHIOrSelect(Instruction &User) {
+  void insertPHIOrSelect(Instruction &User, uint64_t Offset) {
     uint64_t Size = P.PHIOrSelectSizes.lookup(&User).first;
 
     // For PHI and select operands outside the alloca, we can't nuke the entire
@@ -869,13 +874,13 @@
       return;
     }
 
-    insertUse(Size, User);
+    insertUse(User, Offset, Size);
   }
   void visitPHINode(PHINode &PN) {
     if (PN.use_empty())
       return markAsDead(PN);
 
-    insertPHIOrSelect(PN);
+    insertPHIOrSelect(PN, Offset);
   }
   void visitSelectInst(SelectInst &SI) {
     if (SI.use_empty())
@@ -890,7 +895,7 @@
       return;
     }
 
-    insertPHIOrSelect(SI);
+    insertPHIOrSelect(SI, Offset);
   }
 
   /// \brief Unreachable, we've already visited the alloca once.

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