[llvm] [MergeFunctions] Add support to run the pass over a set of function pointers (PR #111045)

[Nikita Popov via llvm-commits]

================
@@ -0,0 +1,249 @@
+//===- MergeFunctionsTest.cpp - Unit tests for MergeFunctionsPass ---------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/IPO/MergeFunctions.h"
+
+#include "llvm/ADT/SetVector.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+#include <memory>
+
+using namespace llvm;
+
+namespace {
+
+TEST(MergeFunctions, TrueOutputModuleTest) {
+  LLVMContext Ctx;
+  SMDiagnostic Err;
+  std::unique_ptr<Module> M(parseAssemblyString(R"invalid(
+        @.str = private unnamed_addr constant [10 x i8] c"On f: %d\0A\00", align 1
+        @.str.1 = private unnamed_addr constant [13 x i8] c"On main: %d\0A\00", align 1
+
+        define dso_local i32 @f(i32 noundef %arg) {
+            entry:
+                %add109 = call i32 @_slice_add10(i32 %arg)
+                %call = call i32 (ptr, ...) @printf(ptr noundef @.str, i32 noundef %add109)
+                ret i32 %add109
+        }
+
+        declare i32 @printf(ptr noundef, ...)
+
+        define dso_local i32 @main(i32 noundef %argc, ptr noundef %argv) {
+            entry:
+                %add99 = call i32 @_slice_add10(i32 %argc)
+                %call = call i32 @f(i32 noundef 2)
+                %sub = sub nsw i32 %call, 6
+                %call10 = call i32 (ptr, ...) @printf(ptr noundef @.str.1, i32 noundef %add99)
+                ret i32 %add99
+        }
+
+        define internal i32 @_slice_add10(i32 %arg) {
+            sliceclone_entry:
+                %0 = mul nsw i32 %arg, %arg
+                %1 = mul nsw i32 %0, 2
+                %2 = mul nsw i32 %1, 2
+                %3 = mul nsw i32 %2, 2
+                %4 = add nsw i32 %3, 2
+                ret i32 %4
+        }
+
+        define internal i32 @_slice_add10_alt(i32 %arg) {
+            sliceclone_entry:
+                %0 = mul nsw i32 %arg, %arg
+                %1 = mul nsw i32 %0, 2
+                %2 = mul nsw i32 %1, 2
+                %3 = mul nsw i32 %2, 2
+                %4 = add nsw i32 %3, 2
+                ret i32 %4
+        }
+    )invalid",
+                                                Err, Ctx));
+
+  // Expects true after merging _slice_add10 and _slice_add10_alt
+  EXPECT_TRUE(MergeFunctionsPass::runOnModule(*M));
+}
+
+TEST(MergeFunctions, TrueOutputFunctionsTest) {
+  LLVMContext Ctx;
+  SMDiagnostic Err;
+  std::unique_ptr<Module> M(parseAssemblyString(R"invalid(
+        @.str = private unnamed_addr constant [10 x i8] c"On f: %d\0A\00", align 1
+        @.str.1 = private unnamed_addr constant [13 x i8] c"On main: %d\0A\00", align 1
+
+        define dso_local i32 @f(i32 noundef %arg) {
+            entry:
+                %add109 = call i32 @_slice_add10(i32 %arg)
+                %call = call i32 (ptr, ...) @printf(ptr noundef @.str, i32 noundef %add109)
+                ret i32 %add109
+        }
+
+        declare i32 @printf(ptr noundef, ...)
+
+        define dso_local i32 @main(i32 noundef %argc, ptr noundef %argv) {
+            entry:
+                %add99 = call i32 @_slice_add10(i32 %argc)
+                %call = call i32 @f(i32 noundef 2)
+                %sub = sub nsw i32 %call, 6
+                %call10 = call i32 (ptr, ...) @printf(ptr noundef @.str.1, i32 noundef %add99)
+                ret i32 %add99
+        }
+
+        define internal i32 @_slice_add10(i32 %arg) {
+            sliceclone_entry:
+                %0 = mul nsw i32 %arg, %arg
+                %1 = mul nsw i32 %0, 2
+                %2 = mul nsw i32 %1, 2
+                %3 = mul nsw i32 %2, 2
+                %4 = add nsw i32 %3, 2
+                ret i32 %4
+        }
+
+        define internal i32 @_slice_add10_alt(i32 %arg) {
+            sliceclone_entry:
+                %0 = mul nsw i32 %arg, %arg
+                %1 = mul nsw i32 %0, 2
+                %2 = mul nsw i32 %1, 2
+                %3 = mul nsw i32 %2, 2
+                %4 = add nsw i32 %3, 2
+                ret i32 %4
+        }
+    )invalid",
+                                                Err, Ctx));
+
+  SetVector<Function *> FunctionsSet;
+  for (Function &F : *M)
+    FunctionsSet.insert(&F);
+
+  DenseMap<Function *, Function *> MergeResult =
+      MergeFunctionsPass::runOnFunctions(FunctionsSet.getArrayRef());
+
+  // Expects that both functions (_slice_add10 and _slice_add10_alt)
+  // be mapped to the same new function
+  EXPECT_TRUE(!MergeResult.empty());
+  Function *NewFunction = M->getFunction("_slice_add10");
+  for (auto P : MergeResult)
+    if (P.second)
+      EXPECT_EQ(P.second, NewFunction);
+}
+
+TEST(MergeFunctions, FalseOutputModuleTest) {
+  LLVMContext Ctx;
+  SMDiagnostic Err;
+  std::unique_ptr<Module> M(parseAssemblyString(R"invalid(
+        @.str = private unnamed_addr constant [10 x i8] c"On f: %d\0A\00", align 1
+        @.str.1 = private unnamed_addr constant [13 x i8] c"On main: %d\0A\00", align 1
+
+        define dso_local i32 @f(i32 noundef %arg) {
+            entry:
+                %add109 = call i32 @_slice_add10(i32 %arg)
+                %call = call i32 (ptr, ...) @printf(ptr noundef @.str, i32 noundef %add109)
+                ret i32 %add109
+        }
+
+        declare i32 @printf(ptr noundef, ...)
+
+        define dso_local i32 @main(i32 noundef %argc, ptr noundef %argv) {
+            entry:
+                %add99 = call i32 @_slice_add10(i32 %argc)
+                %call = call i32 @f(i32 noundef 2)
+                %sub = sub nsw i32 %call, 6
+                %call10 = call i32 (ptr, ...) @printf(ptr noundef @.str.1, i32 noundef %add99)
+                ret i32 %add99
+        }
+
+        define internal i32 @_slice_add10(i32 %arg) {
+            sliceclone_entry:
+                %0 = mul nsw i32 %arg, %arg
+                %1 = mul nsw i32 %0, 2
+                %2 = mul nsw i32 %1, 2
+                %3 = mul nsw i32 %2, 2
+                %4 = add nsw i32 %3, 2
+                ret i32 %4
+        }
+
+        define internal i32 @_slice_add10_alt(i32 %arg) {
+            sliceclone_entry:
+                %0 = mul nsw i32 %arg, %arg
+                %1 = mul nsw i32 %0, 2
+                %2 = mul nsw i32 %1, 2
+                %3 = mul nsw i32 %2, 2
+                %4 = add nsw i32 %3, 2
+                ret i32 %0
+        }
+    )invalid",
+                                                Err, Ctx));
+
+  // Expects false after trying to merge _slice_add10 and _slice_add10_alt
+  EXPECT_FALSE(MergeFunctionsPass::runOnModule(*M));
+}
+
+TEST(MergeFunctions, FalseOutputFunctionsTest) {
+  LLVMContext Ctx;
+  SMDiagnostic Err;
+  std::unique_ptr<Module> M(parseAssemblyString(R"invalid(
+        @.str = private unnamed_addr constant [10 x i8] c"On f: %d\0A\00", align 1
+        @.str.1 = private unnamed_addr constant [13 x i8] c"On main: %d\0A\00", align 1
+
+        define dso_local i32 @f(i32 noundef %arg) {
+            entry:
+                %add109 = call i32 @_slice_add10(i32 %arg)
+                %call = call i32 (ptr, ...) @printf(ptr noundef @.str, i32 noundef %add109)
+                ret i32 %add109
+        }
+
+        declare i32 @printf(ptr noundef, ...)
+
+        define dso_local i32 @main(i32 noundef %argc, ptr noundef %argv) {
+            entry:
+                %add99 = call i32 @_slice_add10(i32 %argc)
+                %call = call i32 @f(i32 noundef 2)
+                %sub = sub nsw i32 %call, 6
+                %call10 = call i32 (ptr, ...) @printf(ptr noundef @.str.1, i32 noundef %add99)
+                ret i32 %add99
+        }
+
+        define internal i32 @_slice_add10(i32 %arg) {
+            sliceclone_entry:
+                %0 = mul nsw i32 %arg, %arg
+                %1 = mul nsw i32 %0, 2
+                %2 = mul nsw i32 %1, 2
+                %3 = mul nsw i32 %2, 2
+                %4 = add nsw i32 %3, 2
+                ret i32 %4
+        }
+
+        define internal i32 @_slice_add10_alt(i32 %arg) {
+            sliceclone_entry:
+                %0 = mul nsw i32 %arg, %arg
+                %1 = mul nsw i32 %0, 2
+                %2 = mul nsw i32 %1, 2
+                %3 = mul nsw i32 %2, 2
+                %4 = add nsw i32 %3, 2
+                ret i32 %0
+        }
+    )invalid",
+                                                Err, Ctx));
+
+  SetVector<Function *> FunctionsSet;
+  for (Function &F : *M)
+    FunctionsSet.insert(&F);
+
+  DenseMap<Function *, Function *> MergeResult =
+      MergeFunctionsPass::runOnFunctions(FunctionsSet.getArrayRef());
+
+  for (auto P : MergeResult)
+    std::cout << P.first << " " << P.second << "\n";
----------------
nikic wrote:

Sorry for not noticing this before, but it looks like there's some leftover debugging code here.

https://github.com/llvm/llvm-project/pull/111045