[llvm] [IRBuilder] Add CreateNonnullAssumption and use it in InstCombine (PR #195935)

[Nikolas Klauser via llvm-commits]

https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/195935

None

>From 4e5d614856124f35a60fa6cb78d2c795288e761e Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Tue, 5 May 2026 22:47:53 +0200
Subject: [PATCH] [IRBuilder] Add CreateNonnullAssumption and use it in
 InstCombine

---
 llvm/include/llvm/IR/IRBuilder.h                     | 6 +++++-
 llvm/lib/IR/IRBuilder.cpp                            | 9 ++++++++-
 llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp | 9 ++-------
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/llvm/include/llvm/IR/IRBuilder.h b/llvm/include/llvm/IR/IRBuilder.h
index d3c782a7b4a48..e28a9027740a3 100644
--- a/llvm/include/llvm/IR/IRBuilder.h
+++ b/llvm/include/llvm/IR/IRBuilder.h
@@ -2824,10 +2824,14 @@ class IRBuilderBase {
                                                Value *Alignment,
                                                Value *OffsetValue = nullptr);
 
-  /// Create an assume intrinsic call that represents an dereferencable
+  /// Create an assume intrinsic call that represents a dereferencable
   /// assumption on the provided pointer.
   LLVM_ABI CallInst *CreateDereferenceableAssumption(Value *PtrValue,
                                                      Value *SizeValue);
+
+  /// Create an assume intrinsic call that represents a nonnull assumption on
+  /// the provided pointer.
+  LLVM_ABI CallInst *CreateNonnullAssumption(Value *PtrValue);
 };
 
 /// This provides a uniform API for creating instructions and inserting
diff --git a/llvm/lib/IR/IRBuilder.cpp b/llvm/lib/IR/IRBuilder.cpp
index b322d5e0d0650..09945044c79a1 100644
--- a/llvm/lib/IR/IRBuilder.cpp
+++ b/llvm/lib/IR/IRBuilder.cpp
@@ -1386,13 +1386,20 @@ CallInst *IRBuilderBase::CreateAlignmentAssumption(const DataLayout &DL,
 CallInst *IRBuilderBase::CreateDereferenceableAssumption(Value *PtrValue,
                                                          Value *SizeValue) {
   assert(isa<PointerType>(PtrValue->getType()) &&
-         "trying to create an deferenceable assumption on a non-pointer?");
+         "trying to create a deferenceable assumption on a non-pointer?");
   SmallVector<Value *, 4> Vals({PtrValue, SizeValue});
   OperandBundleDefT<Value *> DereferenceableOpB("dereferenceable", Vals);
   return CreateAssumption(ConstantInt::getTrue(getContext()),
                           {DereferenceableOpB});
 }
 
+CallInst *IRBuilderBase::CreateNonnullAssumption(Value *PtrValue) {
+  assert(isa<PointerType>(PtrValue->getType()) &&
+         "trying to create a nonnull assumption on a non-pointer?");
+  return CreateAssumption(ConstantInt::getTrue(getContext()),
+                          OperandBundleDef("nonnull", PtrValue));
+}
+
 IRBuilderDefaultInserter::~IRBuilderDefaultInserter() = default;
 IRBuilderCallbackInserter::~IRBuilderCallbackInserter() = default;
 IRBuilderFolder::~IRBuilderFolder() = default;
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 7244981b7fa5b..da258b3b34e27 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -3718,13 +3718,8 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     if (match(IIOperand,
               m_SpecificICmp(ICmpInst::ICMP_NE, m_Value(A), m_Zero())) &&
         A->getType()->isPointerTy()) {
-      if (auto *Replacement = buildAssumeFromKnowledge(
-              {RetainedKnowledge{Attribute::NonNull, 0, A}}, Next, &AC, &DT)) {
-
-        InsertNewInstBefore(Replacement, Next->getIterator());
-        AC.registerAssumption(Replacement);
-        return RemoveConditionFromAssume(II);
-      }
+      Builder.CreateNonnullAssumption(A);
+      return eraseInstFromFunction(*II);
     }
 
     // Convert alignment assume like: