[llvm] [LVI] Handle nonnull attributes at callsite (PR #125377)

[Nikita Popov via llvm-commits]

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@@ -780,12 +780,25 @@ void LazyValueInfoImpl::intersectAssumeOrGuardBlockValueConstantRange(
   }
 
   if (BBLV.isOverdefined()) {
-    // Check whether we're checking at the terminator, and the pointer has
-    // been dereferenced in this block.
-    PointerType *PTy = dyn_cast<PointerType>(Val->getType());
-    if (PTy && BB->getTerminator() == BBI &&
-        isNonNullAtEndOfBlock(Val, BB))
-      BBLV = ValueLatticeElement::getNot(ConstantPointerNull::get(PTy));
+    if (PointerType *PTy = dyn_cast<PointerType>(Val->getType())) {
+      // Check whether we're checking at the terminator, and the pointer has
+      // been dereferenced in this block.
+      if (BB->getTerminator() == BBI && isNonNullAtEndOfBlock(Val, BB))
+        BBLV = ValueLatticeElement::getNot(ConstantPointerNull::get(PTy));
+      else {
+        for (Use &U : Val->uses()) {
+          if (auto *CB = dyn_cast<CallBase>(U.getUser())) {
+            if (CB->isArgOperand(&U) &&
+                CB->paramHasNonNullAttr(CB->getArgOperandNo(&U),
+                                        /*AllowUndefOrPoison=*/false) &&
+                isValidAssumeForContext(CB, BBI)) {
+              BBLV = ValueLatticeElement::getNot(ConstantPointerNull::get(PTy));
+              break;
+            }
+          }
+        }
+      }
+    }
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nikic wrote:

This should be in be handled as part of AddNonNullPointersByInstruction: https://github.com/llvm/llvm-project/blob/c3bacf06324b96fb5d48c781b723a29c0e2cf4ca/llvm/lib/Analysis/LazyValueInfo.cpp#L631.

https://github.com/llvm/llvm-project/pull/125377