[TLI] Fix replace-with-veclib crash with invalid arguments

llvm/lib/CodeGen/ReplaceWithVeclib.cpp

@@ -185,7 +185,7 @@ static bool replaceWithCallToVeclib(const TargetLibraryInfo &TLI,
       Type *OrigTy = CI->getArgOperand(VFParam.ParamPos)->getType();
       if (OrigTy->isVectorTy() != (VFParam.ParamKind == VFParamKind::Vector)) {
         LLVM_DEBUG(dbgs() << DEBUG_TYPE
-                          << ": Will not replace: wrong type at index: "
+                          << ": Will not replace. Wrong type at index "
                           << VFParam.ParamPos << ": " << *OrigTy << "\n");
         return false;
       }
@@ -245,6 +245,9 @@ PreservedAnalyses ReplaceWithVeclib::run(Function &F,
   const TargetLibraryInfo &TLI = AM.getResult<TargetLibraryAnalysis>(F);
   auto Changed = runImpl(TLI, F);
   if (Changed) {
+    LLVM_DEBUG(dbgs() << "Instructions replaced with vector libraries: "
+                      << NumCallsReplaced << "\n");
+
     PreservedAnalyses PA;
     PA.preserveSet<CFGAnalyses>();
     PA.preserve<TargetLibraryAnalysis>();

llvm/unittests/Analysis/ReplaceWithVecLibTest.cpp

@@ -32,14 +32,27 @@ static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
 /// the input IR) does not match the replacement function (derived from the
 /// VecDesc mapping).
 class ReplaceWithVecLibTest : public ::testing::Test {
+
+  std::string getLastLine(std::string Out) {
+    // remove ending '\n' if it exists
+    if (!Out.empty() && *(Out.cend() - 1) == '\n')
+      Out.pop_back();
+
+    size_t LastNL = Out.find_last_of('\n');
+    return (LastNL == std::string::npos) ? Out : Out.substr(LastNL + 1);
+  }
+
 protected:
   LLVMContext Ctx;
 
   /// Creates TLII using the given \p VD, and then runs the ReplaceWithVeclib
   /// pass. The pass should not crash even when the replacement function
   /// (derived from the \p VD mapping) does not match the function to be
   /// replaced (from the input \p IR).
-  bool run(const VecDesc &VD, const char *IR) {
+  ///
+  /// \returns the last line of the standard error to be compared for
+  /// correctness.
+  std::string run(const VecDesc &VD, const char *IR) {
     // Create TLII and register it with FAM so it's preserved when
     // ReplaceWithVeclib pass runs.
     TargetLibraryInfoImpl TLII = TargetLibraryInfoImpl(Triple());
@@ -53,9 +66,12 @@ class ReplaceWithVecLibTest : public ::testing::Test {
     std::unique_ptr<Module> M = parseIR(Ctx, IR);
     PassBuilder PB;
     PB.registerFunctionAnalyses(FAM);
-    FPM.run(*M->getFunction("foo"), FAM);
 
-    return true;
+    // Enable debugging and capture std error
+    llvm::DebugFlag = true;
+    testing::internal::CaptureStderr();
+    FPM.run(*M->getFunction("foo"), FAM);
+    return getLastLine(testing::internal::GetCapturedStderr());
   }
 };
 
@@ -76,7 +92,8 @@ TEST_F(ReplaceWithVecLibTest, TestValidMapping) {
   VecDesc CorrectVD = {"llvm.powi.f32.i32", "_ZGVsMxvu_powi",
                        ElementCount::getScalable(4), /*Masked*/ true,
                        "_ZGVsMxvu"};
-  EXPECT_TRUE(run(CorrectVD, IR));
+  EXPECT_EQ(run(CorrectVD, IR),
+            "Instructions replaced with vector libraries: 1");
 }
 
 // The VFABI prefix in TLI describes signature which is not matching the powi
@@ -85,5 +102,7 @@ TEST_F(ReplaceWithVecLibTest, TestInvalidMapping) {
   VecDesc IncorrectVD = {"llvm.powi.f32.i32", "_ZGVsMxvv_powi",
                          ElementCount::getScalable(4), /*Masked*/ true,
                          "_ZGVsMxvv"};
-  EXPECT_TRUE(run(IncorrectVD, IR));
+  EXPECT_EQ(
+      run(IncorrectVD, IR),
+      "replace-with-veclib: Will not replace. Wrong type at index 1: i32");
 }