[PATCH] InstCombine: propagate deref and nonNull return attributes

[Ramkumar Ramachandra]

Hi reames, dexonsmith,

gc.relocate is missing deref propagation, and assume is missing nonNull
propagation for call/invoke LHS. Fill these gaps.

http://reviews.llvm.org/D7107

Files:
  lib/Transforms/InstCombine/InstCombineCalls.cpp

Index: lib/Transforms/InstCombine/InstCombineCalls.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1068,24 +1068,30 @@
       return EraseInstFromFunction(*II);
     }
 
-    // assume( (load addr) != null ) -> add 'nonnull' metadata to load
-    // (if assume is valid at the load)
     if (ICmpInst* ICmp = dyn_cast<ICmpInst>(IIOperand)) {
       Value *LHS = ICmp->getOperand(0);
       Value *RHS = ICmp->getOperand(1);
       if (ICmpInst::ICMP_NE == ICmp->getPredicate() &&
-          isa<LoadInst>(LHS) &&
           isa<Constant>(RHS) &&
           RHS->getType()->isPointerTy() &&
           cast<Constant>(RHS)->isNullValue()) {
-        LoadInst* LI = cast<LoadInst>(LHS);
-        if (isValidAssumeForContext(II, LI, DL, DT)) {
-          MDNode *MD = MDNode::get(II->getContext(), None);
-          LI->setMetadata(LLVMContext::MD_nonnull, MD);
-          return EraseInstFromFunction(*II);
+        // assume( (load addr) != null ) -> add 'nonnull' metadata to load
+        // (if assume is valid at the load)
+        if (LoadInst* LI = dyn_cast<LoadInst>(LHS)) {
+          if (isValidAssumeForContext(II, LI, DL, DT)) {
+            MDNode *MD = MDNode::get(II->getContext(), None);
+            LI->setMetadata(LLVMContext::MD_nonnull, MD);
+            return EraseInstFromFunction(*II);
+          }
         }
+        else if (CallInst *I = dyn_cast<CallInst>(LHS)) {
+          // assume( (call|invoke) != null ) -> add 'nonnull' return attribute
+          if (isValidAssumeForContext(II, I, DL, DT))
+            I->addAttribute(AttributeSet::ReturnIndex, Attribute::NonNull);
+        } else if (InvokeInst *I = dyn_cast<InvokeInst>(LHS))
+          if (isValidAssumeForContext(II, I, DL, DT))
+            I->addAttribute(AttributeSet::ReturnIndex, Attribute::NonNull);
       }
-      // TODO: apply nonnull return attributes to calls and invokes
       // TODO: apply range metadata for range check patterns?
     }
     // If there is a dominating assume with the same condition as this one,
@@ -1126,7 +1132,9 @@
     if (isKnownNonNull(DerivedPtr))
       II->addAttribute(AttributeSet::ReturnIndex, Attribute::NonNull);
 
-    // TODO: dereferenceable -> deref attribute
+    // isDereferenceablePointer -> deref attribute
+    if (DerivedPtr->isDereferenceablePointer())
+      II->addAttribute(AttributeSet::ReturnIndex, Attribute::Dereferenceable);
 
     // TODO: bitcast(relocate(p)) -> relocate(bitcast(p))
     // Canonicalize on the type from the uses to the defs

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