[clang] [CIR] Add assume_separate_storage operation (PR #149696)

[Sirui Mu via cfe-commits]

https://github.com/Lancern created https://github.com/llvm/llvm-project/pull/149696

This patch adds the `cir.assume_separate_storage` operation for the `__builtin_assume_separate_storage` builtin function.

>From 54fc10bc7152748c2e889e5c20948a3cb99c1912 Mon Sep 17 00:00:00 2001
From: Sirui Mu <msrlancern at gmail.com>
Date: Sun, 20 Jul 2025 16:22:27 +0800
Subject: [PATCH] [CIR] Add assume_separate_storage operation

This patch adds the `cir.assume_separate_storage` operation for the
`__builtin_assume_separate_storage` builtin function.
---
 clang/include/clang/CIR/Dialect/IR/CIROps.td  | 20 +++++++++++++++++++
 clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp       |  7 +++++++
 .../CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp | 12 +++++++++++
 .../CIR/Lowering/DirectToLLVM/LowerToLLVM.h   | 10 ++++++++++
 clang/test/CIR/CodeGen/builtin_call.cpp       | 16 +++++++++++++++
 5 files changed, 65 insertions(+)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 01c5055484185..30646008ccff0 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -3004,6 +3004,26 @@ def CIR_AssumeOp : CIR_Op<"assume"> {
   }];
 }
 
+def CIR_AssumeSepStorageOp : CIR_Op<"assume_separate_storage",
+                                    [SameTypeOperands]> {
+  let summary =
+      "Tell the optimizer that two pointers point to different allocations";
+  let description = [{
+    The `cir.assume.separate_storage` operation takes two pointers as arguments,
+    and the operation tells the optimizer that these two pointers point to
+    different allocations.
+
+    This operation corresponds to the `__builtin_assume_separate_storage`
+    builtin function.
+  }];
+
+  let arguments = (ins CIR_VoidPtrType:$ptr1, CIR_VoidPtrType:$ptr2);
+
+  let assemblyFormat = [{
+    $ptr1 `,` $ptr2 `:` qualified(type($ptr1)) attr-dict
+  }];
+}
+
 //===----------------------------------------------------------------------===//
 // Branch Probability Operations
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
index 61d1c54ee9ec9..ef136f80637f3 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
@@ -121,6 +121,13 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
     return RValue::get(nullptr);
   }
 
+  case Builtin::BI__builtin_assume_separate_storage: {
+    mlir::Value value0 = emitScalarExpr(e->getArg(0));
+    mlir::Value value1 = emitScalarExpr(e->getArg(1));
+    builder.create<cir::AssumeSepStorageOp>(loc, value0, value1);
+    return RValue::get(nullptr);
+  }
+
   case Builtin::BI__builtin_complex: {
     mlir::Value real = emitScalarExpr(e->getArg(0));
     mlir::Value imag = emitScalarExpr(e->getArg(1));
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index f075be8a9eed5..3cd7de0a56bc3 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -460,6 +460,17 @@ mlir::LogicalResult CIRToLLVMAssumeOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+mlir::LogicalResult CIRToLLVMAssumeSepStorageOpLowering::matchAndRewrite(
+    cir::AssumeSepStorageOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  auto cond = rewriter.create<mlir::LLVM::ConstantOp>(op.getLoc(),
+                                                      rewriter.getI1Type(), 1);
+  rewriter.replaceOpWithNewOp<mlir::LLVM::AssumeOp>(
+      op, cond, mlir::LLVM::AssumeSeparateStorageTag{}, adaptor.getPtr1(),
+      adaptor.getPtr2());
+  return mlir::success();
+}
+
 mlir::LogicalResult CIRToLLVMBitClrsbOpLowering::matchAndRewrite(
     cir::BitClrsbOp op, OpAdaptor adaptor,
     mlir::ConversionPatternRewriter &rewriter) const {
@@ -2066,6 +2077,7 @@ void ConvertCIRToLLVMPass::runOnOperation() {
   patterns.add<
       // clang-format off
                CIRToLLVMAssumeOpLowering,
+               CIRToLLVMAssumeSepStorageOpLowering,
                CIRToLLVMBaseClassAddrOpLowering,
                CIRToLLVMBinOpLowering,
                CIRToLLVMBitClrsbOpLowering,
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
index 3faf1e900848e..2911ced66e58e 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
@@ -44,6 +44,16 @@ class CIRToLLVMAssumeOpLowering
                   mlir::ConversionPatternRewriter &) const override;
 };
 
+class CIRToLLVMAssumeSepStorageOpLowering
+    : public mlir::OpConversionPattern<cir::AssumeSepStorageOp> {
+public:
+  using mlir::OpConversionPattern<cir::AssumeSepStorageOp>::OpConversionPattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(cir::AssumeSepStorageOp op, OpAdaptor,
+                  mlir::ConversionPatternRewriter &) const override;
+};
+
 class CIRToLLVMBitClrsbOpLowering
     : public mlir::OpConversionPattern<cir::BitClrsbOp> {
 public:
diff --git a/clang/test/CIR/CodeGen/builtin_call.cpp b/clang/test/CIR/CodeGen/builtin_call.cpp
index ad0e478040836..d9a70683a4dbc 100644
--- a/clang/test/CIR/CodeGen/builtin_call.cpp
+++ b/clang/test/CIR/CodeGen/builtin_call.cpp
@@ -111,6 +111,22 @@ void assume(bool arg) {
 // OGCG:   call void @llvm.assume(i1 %{{.+}})
 // OGCG: }
 
+void assume_separate_storage(void *p1, void *p2) {
+  __builtin_assume_separate_storage(p1, p2);
+}
+
+// CIR: cir.func{{.*}} @_Z23assume_separate_storagePvS_
+// CIR:   cir.assume_separate_storage %{{.+}}, %{{.+}} : !cir.ptr<!void>
+// CIR: }
+
+// LLVM: define {{.*}}void @_Z23assume_separate_storagePvS_
+// LLVM:   call void @llvm.assume(i1 true) [ "separate_storage"(ptr %{{.+}}, ptr %{{.+}}) ]
+// LLVM: }
+
+// OGCG: define {{.*}}void @_Z23assume_separate_storagePvS_
+// OGCG:   call void @llvm.assume(i1 true) [ "separate_storage"(ptr %{{.+}}, ptr %{{.+}}) ]
+// OGCG: }
+
 void expect(int x, int y) {
   __builtin_expect(x, y);
 }