Add unit tests for getUnderlyingObject

[MatzeB]

No description provided.

[llvmbot]

@llvm/pr-subscribers-llvm-analysis

Author: Matthias Braun (MatzeB)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/89120.diff

1 Files Affected:

• (modified) llvm/unittests/Analysis/ValueTrackingTest.cpp (+72)

diff --git a/llvm/unittests/Analysis/ValueTrackingTest.cpp b/llvm/unittests/Analysis/ValueTrackingTest.cpp
index 8738af91b652b8..c59ed041373001 100644
--- a/llvm/unittests/Analysis/ValueTrackingTest.cpp
+++ b/llvm/unittests/Analysis/ValueTrackingTest.cpp
@@ -1247,6 +1247,78 @@ TEST_F(ValueTrackingTest, computePtrAlignment) {
   EXPECT_EQ(getKnownAlignment(A, DL, CxtI3, &AC, &DT), Align(16));
 }
 
+TEST_F(ValueTrackingTest, getUnderlyingObjectCastsAliases) {
+  parseAssembly(R"IR(
+    @gvar = global i32 0
+    @alias = alias i32, i32* @gvar
+    @alias_interposable = weak alias i32, i32* @gvar
+    define void @test() {
+      %A = call ptr @llvm.ssa.copy.p0(ptr @gvar)
+      %A2 = call ptr @llvm.ssa.copy.p0(ptr bitcast(ptr @gvar to ptr))
+      %A3 = call ptr addrspace(42) @llvm.ssa.copy.p42(ptr addrspace(42) addrspacecast(ptr @gvar to ptr addrspace(42)))
+      %A4 = call ptr @llvm.ssa.copy.p0(ptr @alias)
+      %A5 = call ptr @llvm.ssa.copy.p0(ptr @alias_interposable)
+      ret void
+    }
+)IR");
+  Value *gvar = A->getOperand(0);
+  EXPECT_EQ(getUnderlyingObject(A->getOperand(0)), gvar);
+  EXPECT_EQ(getUnderlyingObject(A2->getOperand(0)), gvar);
+  EXPECT_EQ(getUnderlyingObject(A3->getOperand(0)), gvar);
+  EXPECT_EQ(getUnderlyingObject(A4->getOperand(0)), gvar);
+  EXPECT_EQ(getUnderlyingObject(A4->getOperand(0)), gvar);
+  // should not skip interposable alias
+  EXPECT_EQ(getUnderlyingObject(A5->getOperand(0)), A5->getOperand(0));
+}
+
+TEST_F(ValueTrackingTest, getUnderlyingObjectIntrinsics) {
+  parseAssembly(R"IR(
+    define void @test(ptr %arg) {
+      ; intrinsic with Return<> arg attribute
+      %A = call ptr @llvm.objc.retain(ptr %arg)
+      %A2 = call ptr @llvm.ssa.copy(ptr %arg)
+      ; special cased intrinsics
+      %A3 = call ptr @llvm.launder.invariant.group(ptr %arg)
+      ret void
+    }
+)IR");
+  Value *arg = F->getArg(0);
+  EXPECT_EQ(getUnderlyingObject(A), arg);
+  EXPECT_EQ(getUnderlyingObject(A2), arg);
+  EXPECT_EQ(getUnderlyingObject(A3), arg);
+}
+
+TEST_F(ValueTrackingTest, getUnderlyingObjectPtrInt) {
+  parseAssembly(R"IR(
+    define void @test(i64 %arg, ptr %arg1) {
+      %A = inttoptr i64 %arg to ptr
+      %t0 = ptrtoint ptr %arg1 to i64
+      %A2 = inttoptr i64 %t0 to ptr
+      ret void
+    }
+)IR");
+  // Should not skip anything here
+  EXPECT_EQ(getUnderlyingObject(A->getOperand(0)), A->getOperand(0));
+  EXPECT_EQ(getUnderlyingObject(A2->getOperand(0)), A2->getOperand(0));
+}
+
+TEST_F(ValueTrackingTest, getUnderlyingObjectPhi) {
+  parseAssembly(R"IR(
+    @gvar = global i32 0
+    define void @test() {
+    entry:
+      %A = call ptr @llvm.ssa.copy.p0(ptr @gvar)
+      br label %block2
+
+    block2:
+      %A2 = phi ptr [ @gvar, %entry ]
+      ret void
+    }
+)IR");
+  Value *gvar = A->getOperand(0);
+  EXPECT_EQ(getUnderlyingObject(A2->getOperand(0)), gvar);
+}
+
 TEST_F(ComputeKnownBitsTest, ComputeKnownBits) {
   parseAssembly(
       "define i32 @test(i32 %a, i32 %b) {\n"

[MatzeB]

Would be good to have some unittests for getUnderlyingObject; that way I can easily add a new one in #88418

[nikic]

TBH I'd rather not have (IR) unit tests unless lit tests are uniquely hard to write for some reason. They are very annoying to update if they ever break. getUnderlyingObject() can be (and is) tested through its impact on alias analysis etc.

[MatzeB]

No problem, this was mostly because I somehow expected reviewers to ask for more tests. Will gladly drop them.