[llvm] [InstCombine][NFC] Replace buildAssumeFromKnowledge with CreateAlignmentAssumption (PR #196254)

[Nikolas Klauser via llvm-commits]

https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/196254

None

>From 1c50dc3dcdcd531bf12c023f7672ece87439bf13 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Thu, 7 May 2026 09:45:01 +0200
Subject: [PATCH] [InstCombine][NFC] Replace buildAssumeFromKnowledge with
 CreateAlignmentAssumption

---
 llvm/include/llvm/IR/IRBuilder.h              |  2 +-
 .../Transforms/Utils/AssumeBundleBuilder.h    |  7 ------
 llvm/lib/IR/IRBuilder.cpp                     |  2 +-
 .../InstCombine/InstCombineCalls.cpp          | 23 ++-----------------
 .../Transforms/Utils/AssumeBundleBuilder.cpp  | 10 --------
 5 files changed, 4 insertions(+), 40 deletions(-)

diff --git a/llvm/include/llvm/IR/IRBuilder.h b/llvm/include/llvm/IR/IRBuilder.h
index e28a9027740a3..ca085bb4aaa11 100644
--- a/llvm/include/llvm/IR/IRBuilder.h
+++ b/llvm/include/llvm/IR/IRBuilder.h
@@ -2807,7 +2807,7 @@ class IRBuilderBase {
   /// specified alignment.
   LLVM_ABI CallInst *CreateAlignmentAssumption(const DataLayout &DL,
                                                Value *PtrValue,
-                                               unsigned Alignment,
+                                               uint64_t Alignment,
                                                Value *OffsetValue = nullptr);
 
   /// Create an assume intrinsic call that represents an alignment
diff --git a/llvm/include/llvm/Transforms/Utils/AssumeBundleBuilder.h b/llvm/include/llvm/Transforms/Utils/AssumeBundleBuilder.h
index 2f45a1c5f5b67..1c0c318c8b0f2 100644
--- a/llvm/include/llvm/Transforms/Utils/AssumeBundleBuilder.h
+++ b/llvm/include/llvm/Transforms/Utils/AssumeBundleBuilder.h
@@ -47,13 +47,6 @@ LLVM_ABI AssumeInst *buildAssumeFromInst(Instruction *I);
 LLVM_ABI bool salvageKnowledge(Instruction *I, AssumptionCache *AC = nullptr,
                                DominatorTree *DT = nullptr);
 
-/// Build and return a new assume created from the provided knowledge
-/// if the knowledge in the assume is fully redundant this will return nullptr
-LLVM_ABI AssumeInst *
-buildAssumeFromKnowledge(ArrayRef<RetainedKnowledge> Knowledge,
-                         Instruction *CtxI, AssumptionCache *AC = nullptr,
-                         DominatorTree *DT = nullptr);
-
 /// This pass attempts to minimize the number of assume without loosing any
 /// information.
 struct AssumeSimplifyPass : public OptionalPassInfoMixin<AssumeSimplifyPass> {
diff --git a/llvm/lib/IR/IRBuilder.cpp b/llvm/lib/IR/IRBuilder.cpp
index 09945044c79a1..706a977a5b6d5 100644
--- a/llvm/lib/IR/IRBuilder.cpp
+++ b/llvm/lib/IR/IRBuilder.cpp
@@ -1363,7 +1363,7 @@ CallInst *IRBuilderBase::CreateAlignmentAssumptionHelper(const DataLayout &DL,
 
 CallInst *IRBuilderBase::CreateAlignmentAssumption(const DataLayout &DL,
                                                    Value *PtrValue,
-                                                   unsigned Alignment,
+                                                   uint64_t Alignment,
                                                    Value *OffsetValue) {
   assert(isa<PointerType>(PtrValue->getType()) &&
          "trying to create an alignment assumption on a non-pointer?");
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index b4e2ebea4d196..be71f2abececb 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -3607,17 +3607,6 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     SmallVector<OperandBundleDef, 4> OpBundles;
     II->getOperandBundlesAsDefs(OpBundles);
 
-    /// This will remove the boolean Condition from the assume given as
-    /// argument and remove the assume if it becomes useless.
-    /// always returns nullptr for use as a return values.
-    auto RemoveConditionFromAssume = [&](Instruction *Assume) -> Instruction * {
-      assert(isa<AssumeInst>(Assume));
-      if (isAssumeWithEmptyBundle(*cast<AssumeInst>(II)))
-        return eraseInstFromFunction(CI);
-      replaceUse(II->getOperandUse(0), ConstantInt::getTrue(II->getContext()));
-      return nullptr;
-    };
-
     // Canonicalize assume(a && b) -> assume(a); assume(b);
     // Note: New assumption intrinsics created here are registered by
     // the InstCombineIRInserter object.
@@ -3706,7 +3695,6 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
       }
     }
 
-    Instruction *Next = II->getNextNode();
     // Convert nonnull assume like:
     // %A = icmp ne i32* %PTR, null
     // call void @llvm.assume(i1 %A)
@@ -3740,15 +3728,8 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
           /// offset and alignment.
           /// TODO: we can generate a GEP instead of merging the alignment with
           /// the offset.
-          RetainedKnowledge RK{Attribute::Alignment,
-                               MinAlign(Offset, AlignMask + 1), A};
-          if (auto *Replacement =
-                  buildAssumeFromKnowledge(RK, Next, &AC, &DT)) {
-
-            Replacement->insertAfter(II->getIterator());
-            AC.registerAssumption(Replacement);
-          }
-          return RemoveConditionFromAssume(II);
+          Builder.CreateAlignmentAssumption(getDataLayout(), A, AlignMask + 1);
+          return eraseInstFromFunction(*II);
         }
       }
     }
diff --git a/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp b/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp
index 8df3be85c9535..26bca70e1056f 100644
--- a/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp
+++ b/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp
@@ -311,16 +311,6 @@ bool llvm::salvageKnowledge(Instruction *I, AssumptionCache *AC,
   return Changed;
 }
 
-AssumeInst *
-llvm::buildAssumeFromKnowledge(ArrayRef<RetainedKnowledge> Knowledge,
-                               Instruction *CtxI, AssumptionCache *AC,
-                               DominatorTree *DT) {
-  AssumeBuilderState Builder(CtxI->getModule(), CtxI, AC, DT);
-  for (const RetainedKnowledge &RK : Knowledge)
-    Builder.addKnowledge(RK);
-  return Builder.build();
-}
-
 RetainedKnowledge llvm::simplifyRetainedKnowledge(AssumeInst *Assume,
                                                   RetainedKnowledge RK,
                                                   AssumptionCache *AC,