[llvm] [SandboxIR] Add pointer-diff utility function (PR #110176)

[via llvm-commits]

================
@@ -54,3 +59,75 @@ define void @foo(ptr %arg0) {
   EXPECT_EQ(sandboxir::Utils::memoryLocationGetOrNone(Ld),
             MemoryLocation::getOrNone(LLVMLd));
 }
+
+TEST_F(UtilsTest, GetPointerDiffInBytes) {
+  parseIR(C, R"IR(
+define void @foo(ptr %ptr) {
+  %gep0 = getelementptr inbounds float, ptr %ptr, i64 0
+  %gep1 = getelementptr inbounds float, ptr %ptr, i64 1
+  %gep2 = getelementptr inbounds float, ptr %ptr, i64 2
+  %gep3 = getelementptr inbounds float, ptr %ptr, i64 3
+
+  %ld0 = load float, ptr %gep0
+  %ld1 = load float, ptr %gep1
+  %ld2 = load float, ptr %gep2
+  %ld3 = load float, ptr %gep3
+
+  %v2ld0 = load <2 x float>, ptr %gep0
+  %v2ld1 = load <2 x float>, ptr %gep1
+  %v2ld2 = load <2 x float>, ptr %gep2
+  %v2ld3 = load <2 x float>, ptr %gep3
+
+  %v3ld0 = load <3 x float>, ptr %gep0
+  %v3ld1 = load <3 x float>, ptr %gep1
+  %v3ld2 = load <3 x float>, ptr %gep2
+  %v3ld3 = load <3 x float>, ptr %gep3
+  ret void
+}
+)IR");
+  llvm::Function &LLVMF = *M->getFunction("foo");
+  DominatorTree DT(LLVMF);
+  TargetLibraryInfoImpl TLII;
+  TargetLibraryInfo TLI(TLII);
+  DataLayout DL(M->getDataLayout());
+  AssumptionCache AC(LLVMF);
+  BasicAAResult BAA(DL, LLVMF, TLI, AC, &DT);
+  AAResults AA(TLI);
+  AA.addAAResult(BAA);
+  LoopInfo LI(DT);
+  ScalarEvolution SE(LLVMF, TLI, AC, DT, LI);
+  sandboxir::Context Ctx(C);
+
+  auto &F = *Ctx.createFunction(&LLVMF);
+  auto &BB = *F.begin();
+  auto It = std::next(BB.begin(), 4);
+  auto *L0 = cast<sandboxir::LoadInst>(&*It++);
+  auto *L1 = cast<sandboxir::LoadInst>(&*It++);
+  auto *L2 = cast<sandboxir::LoadInst>(&*It++);
+  auto *L3 = cast<sandboxir::LoadInst>(&*It++);
+  (void)L3;
+
+  auto *V2L0 = cast<sandboxir::LoadInst>(&*It++);
+  auto *V2L1 = cast<sandboxir::LoadInst>(&*It++);
+  auto *V2L2 = cast<sandboxir::LoadInst>(&*It++);
+  auto *V2L3 = cast<sandboxir::LoadInst>(&*It++);
+
+  auto *V3L0 = cast<sandboxir::LoadInst>(&*It++);
+  (void)V3L0;
+  auto *V3L1 = cast<sandboxir::LoadInst>(&*It++);
+  auto *V3L2 = cast<sandboxir::LoadInst>(&*It++);
+  (void)V3L2;
+  auto *V3L3 = cast<sandboxir::LoadInst>(&*It++);
+  (void)V3L3;
+
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(L0, L1, SE, DL), 4);
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(L0, L2, SE, DL), 8);
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(L1, L0, SE, DL), -4);
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(L0, V2L0, SE, DL), 0);
+
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(L0, V2L1, SE, DL), 4);
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(L0, V3L1, SE, DL), 4);
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(V2L0, V2L2, SE, DL), 8);
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(V2L0, V2L3, SE, DL), 12);
+  EXPECT_EQ(*sandboxir::Utils::getPointerDiffInBytes(V2L3, V2L0, SE, DL), -12);
----------------
vporpo wrote:

How about tests for `atLowerAddress()` ?

https://github.com/llvm/llvm-project/pull/110176