OpaquePtr: add Type parameter to Loads analysis API.

This makes the functions in Loads.h require a type to be specified
independently of the pointer Value so that when pointers have no structure
other than address-space, it can still do its job.

Most callers had an obvious memory operation handy to provide this type, but a
SROA and ArgumentPromotion were doing more complicated analysis. They get
updated to merge the properties of the various instructions they were
considering.

llvm-svn: 365468

1 files changed, 11 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
index cc79afdb05a..33f90d0b01e 100644
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -1190,12 +1190,16 @@ static Type *findCommonType(AllocaSlices::const_iterator B,
 /// FIXME: This should be hoisted into a generic utility, likely in
 /// Transforms/Util/Local.h
 static bool isSafePHIToSpeculate(PHINode &PN) {
+  const DataLayout &DL = PN.getModule()->getDataLayout();
+
   // For now, we can only do this promotion if the load is in the same block
   // as the PHI, and if there are no stores between the phi and load.
   // TODO: Allow recursive phi users.
   // TODO: Allow stores.
   BasicBlock *BB = PN.getParent();
   unsigned MaxAlign = 0;
+  uint64_t APWidth = DL.getIndexTypeSizeInBits(PN.getType());
+  APInt MaxSize(APWidth, 0);
   bool HaveLoad = false;
   for (User *U : PN.users()) {
     LoadInst *LI = dyn_cast<LoadInst>(U);
@@ -1214,15 +1218,15 @@ static bool isSafePHIToSpeculate(PHINode &PN) {
       if (BBI->mayWriteToMemory())
         return false;
 
+    uint64_t Size = DL.getTypeStoreSizeInBits(LI->getType());
     MaxAlign = std::max(MaxAlign, LI->getAlignment());
+    MaxSize = MaxSize.ult(Size) ? APInt(APWidth, Size) : MaxSize;
     HaveLoad = true;
   }
 
   if (!HaveLoad)
     return false;
 
-  const DataLayout &DL = PN.getModule()->getDataLayout();
-
   // We can only transform this if it is safe to push the loads into the
   // predecessor blocks. The only thing to watch out for is that we can't put
   // a possibly trapping load in the predecessor if it is a critical edge.
@@ -1244,7 +1248,7 @@ static bool isSafePHIToSpeculate(PHINode &PN) {
     // If this pointer is always safe to load, or if we can prove that there
     // is already a load in the block, then we can move the load to the pred
     // block.
-    if (isSafeToLoadUnconditionally(InVal, MaxAlign, DL, TI))
+    if (isSafeToLoadUnconditionally(InVal, MaxAlign, MaxSize, DL, TI))
       continue;
 
     return false;
@@ -1334,9 +1338,11 @@ static bool isSafeSelectToSpeculate(SelectInst &SI) {
     // Both operands to the select need to be dereferenceable, either
     // absolutely (e.g. allocas) or at this point because we can see other
     // accesses to it.
-    if (!isSafeToLoadUnconditionally(TValue, LI->getAlignment(), DL, LI))
+    if (!isSafeToLoadUnconditionally(TValue, LI->getType(), LI->getAlignment(),
+                                     DL, LI))
       return false;
-    if (!isSafeToLoadUnconditionally(FValue, LI->getAlignment(), DL, LI))
+    if (!isSafeToLoadUnconditionally(FValue, LI->getType(), LI->getAlignment(),
+                                     DL, LI))
       return false;
   }