[llvm] [SandboxIR] Add utility function to find the base Value for Mem instructions (PR #112030)

[via llvm-commits]

https://github.com/Sterling-Augustine created https://github.com/llvm/llvm-project/pull/112030

None

>From 3a38b6822898393028d6991c5e3d7ef69fb8ac40 Mon Sep 17 00:00:00 2001
From: Sterling Augustine <saugustine at google.com>
Date: Fri, 11 Oct 2024 10:57:25 -0700
Subject: [PATCH] [SandboxIR] Add utility function to find the base Value for
 loads and stores

---
 llvm/include/llvm/SandboxIR/Context.h  |  1 +
 llvm/include/llvm/SandboxIR/Utils.h    | 10 ++++++++
 llvm/unittests/SandboxIR/UtilsTest.cpp | 32 ++++++++++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/llvm/include/llvm/SandboxIR/Context.h b/llvm/include/llvm/SandboxIR/Context.h
index 77924fbcd5acea..1285598a1c0282 100644
--- a/llvm/include/llvm/SandboxIR/Context.h
+++ b/llvm/include/llvm/SandboxIR/Context.h
@@ -68,6 +68,7 @@ class Context {
   }
   /// Get or create a sandboxir::Constant from an existing LLVM IR \p LLVMC.
   Constant *getOrCreateConstant(llvm::Constant *LLVMC);
+  friend class Utils; // For getMemoryBase
 
   // Friends for getOrCreateConstant().
 #define DEF_CONST(ID, CLASS) friend class CLASS;
diff --git a/llvm/include/llvm/SandboxIR/Utils.h b/llvm/include/llvm/SandboxIR/Utils.h
index e4156c6af9a220..b0037723a9e88b 100644
--- a/llvm/include/llvm/SandboxIR/Utils.h
+++ b/llvm/include/llvm/SandboxIR/Utils.h
@@ -49,6 +49,16 @@ class Utils {
     return const_cast<Instruction *>(I);
   }
 
+  /// \Returns the base Value for load or store instruction \p LSI.
+  template <typename LoadOrStoreT>
+  static Value *getMemInstructionBase(const LoadOrStoreT *LSI) {
+    static_assert(std::is_same_v<LoadOrStoreT, LoadInst> ||
+                      std::is_same_v<LoadOrStoreT, StoreInst>,
+                  "Expected sandboxir::Load or sandboxir::Store!");
+    return LSI->Ctx.getOrCreateValue(
+        getUnderlyingObject(LSI->getPointerOperand()->Val));
+  }
+
   /// \Returns the number of bits required to represent the operands or return
   /// value of \p V in \p DL.
   static unsigned getNumBits(Value *V, const DataLayout &DL) {
diff --git a/llvm/unittests/SandboxIR/UtilsTest.cpp b/llvm/unittests/SandboxIR/UtilsTest.cpp
index 90396eaa53ab38..a30fc253a1a742 100644
--- a/llvm/unittests/SandboxIR/UtilsTest.cpp
+++ b/llvm/unittests/SandboxIR/UtilsTest.cpp
@@ -215,3 +215,35 @@ define void @foo(float %arg0, double %arg1, i8 %arg2, i64 %arg3, ptr %arg4) {
   EXPECT_EQ(sandboxir::Utils::getNumBits(L2), 8u);
   EXPECT_EQ(sandboxir::Utils::getNumBits(L3), 64u);
 }
+
+TEST_F(UtilsTest, GetMemBase) {
+  parseIR(C, R"IR(
+define void @foo(ptr %ptrA, float %val, ptr %ptrB) {
+bb:
+  %gepA0 = getelementptr float, ptr %ptrA, i32 0
+  %gepA1 = getelementptr float, ptr %ptrA, i32 1
+  %gepB0 = getelementptr float, ptr %ptrB, i32 0
+  %gepB1 = getelementptr float, ptr %ptrB, i32 1
+  store float %val, ptr %gepA0
+  store float %val, ptr %gepA1
+  store float %val, ptr %gepB0
+  store float %val, ptr %gepB1
+  ret void
+}
+)IR");
+  llvm::Function &Foo = *M->getFunction("foo");
+  sandboxir::Context Ctx(C);
+  sandboxir::Function *F = Ctx.createFunction(&Foo);
+
+  auto It = std::next(F->begin()->begin(), 4);
+  auto *St0 = cast<sandboxir::StoreInst>(&*It++);
+  auto *St1 = cast<sandboxir::StoreInst>(&*It++);
+  auto *St2 = cast<sandboxir::StoreInst>(&*It++);
+  auto *St3 = cast<sandboxir::StoreInst>(&*It++);
+  EXPECT_EQ(sandboxir::Utils::getMemInstructionBase(St0),
+            sandboxir::Utils::getMemInstructionBase(St1));
+  EXPECT_EQ(sandboxir::Utils::getMemInstructionBase(St2),
+            sandboxir::Utils::getMemInstructionBase(St3));
+  EXPECT_NE(sandboxir::Utils::getMemInstructionBase(St0),
+            sandboxir::Utils::getMemInstructionBase(St3));
+}