AA metadata refactoring (introduce AAMDNodes)

In order to enable the preservation of noalias function parameter information
after inlining, and the representation of block-level __restrict__ pointer
information (etc.), additional kinds of aliasing metadata will be introduced.
This metadata needs to be carried around in AliasAnalysis::Location objects
(and MMOs at the SDAG level), and so we need to generalize the current scheme
(which is hard-coded to just one TBAA MDNode*).

This commit introduces only the necessary refactoring to allow for the
introduction of other aliasing metadata types, but does not actually introduce
any (that will come in a follow-up commit). What it does introduce is a new
AAMDNodes structure to hold all of the aliasing metadata nodes associated with
a particular memory-accessing instruction, and uses that structure instead of
the raw MDNode* in AliasAnalysis::Location, etc.

No functionality change intended.

llvm-svn: 213859

1 files changed, 12 insertions, 7 deletions

diff --git a/llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index e2a24a7fd4a..579ce13e0b9 100644
--- a/llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -1333,12 +1333,15 @@ static bool tryToMakeAllocaBePromotable(AllocaInst *AI, const DataLayout *DL) {
         LoadInst *FalseLoad =
           Builder.CreateLoad(SI->getFalseValue(), LI->getName()+".f");
 
-        // Transfer alignment and TBAA info if present.
+        // Transfer alignment and AA info if present.
         TrueLoad->setAlignment(LI->getAlignment());
         FalseLoad->setAlignment(LI->getAlignment());
-        if (MDNode *Tag = LI->getMetadata(LLVMContext::MD_tbaa)) {
-          TrueLoad->setMetadata(LLVMContext::MD_tbaa, Tag);
-          FalseLoad->setMetadata(LLVMContext::MD_tbaa, Tag);
+
+        AAMDNodes Tags;
+        LI->getAAMetadata(Tags);
+        if (Tags) {
+          TrueLoad->setAAMetadata(Tags);
+          FalseLoad->setAAMetadata(Tags);
         }
 
         Value *V = Builder.CreateSelect(SI->getCondition(), TrueLoad, FalseLoad);
@@ -1364,10 +1367,12 @@ static bool tryToMakeAllocaBePromotable(AllocaInst *AI, const DataLayout *DL) {
     PHINode *NewPN = PHINode::Create(LoadTy, PN->getNumIncomingValues(),
                                      PN->getName()+".ld", PN);
 
-    // Get the TBAA tag and alignment to use from one of the loads.  It doesn't
+    // Get the AA tags and alignment to use from one of the loads.  It doesn't
     // matter which one we get and if any differ, it doesn't matter.
     LoadInst *SomeLoad = cast<LoadInst>(PN->user_back());
-    MDNode *TBAATag = SomeLoad->getMetadata(LLVMContext::MD_tbaa);
+
+    AAMDNodes AATags;
+    SomeLoad->getAAMetadata(AATags);
     unsigned Align = SomeLoad->getAlignment();
 
     // Rewrite all loads of the PN to use the new PHI.
@@ -1389,7 +1394,7 @@ static bool tryToMakeAllocaBePromotable(AllocaInst *AI, const DataLayout *DL) {
                             PN->getName() + "." + Pred->getName(),
                             Pred->getTerminator());
         Load->setAlignment(Align);
-        if (TBAATag) Load->setMetadata(LLVMContext::MD_tbaa, TBAATag);
+        if (AATags) Load->setAAMetadata(AATags);
       }
 
       NewPN->addIncoming(Load, Pred);