Reapply [TLI] Fix replace-with-veclib crash with invalid arguments (#77945)

Fix a crash of `replace-with-veclib` pass, when the arguments of the TLI
mapping do not match the original call.
Now, it simply ignores such cases.

Test require assertions as it accesses programmatically the debug log.

Reapplies reverted PR #77112

llvm/lib/CodeGen/ReplaceWithVeclib.cpp

@@ -111,7 +111,8 @@ static bool replaceWithCallToVeclib(const TargetLibraryInfo &TLI,
   SmallVector<Type *, 8> ScalarArgTypes;
   std::string ScalarName;
   Function *FuncToReplace = nullptr;
-  if (auto *CI = dyn_cast<CallInst>(&I)) {
+  auto *CI = dyn_cast<CallInst>(&I);
+  if (CI) {
     FuncToReplace = CI->getCalledFunction();
     Intrinsic::ID IID = FuncToReplace->getIntrinsicID();
     assert(IID != Intrinsic::not_intrinsic && "Not an intrinsic");
@@ -168,12 +169,36 @@ static bool replaceWithCallToVeclib(const TargetLibraryInfo &TLI,
   if (!OptInfo)
     return false;
 
+  // There is no guarantee that the vectorized instructions followed the VFABI
+  // specification when being created, this is why we need to add extra check to
+  // make sure that the operands of the vector function obtained via VFABI match
+  // the operands of the original vector instruction.
+  if (CI) {
+    for (auto VFParam : OptInfo->Shape.Parameters) {
+      if (VFParam.ParamKind == VFParamKind::GlobalPredicate)
+        continue;
+
+      // tryDemangleForVFABI must return valid ParamPos, otherwise it could be
+      // a bug in the VFABI parser.
+      assert(VFParam.ParamPos < CI->arg_size() &&
+             "ParamPos has invalid range.");
+      Type *OrigTy = CI->getArgOperand(VFParam.ParamPos)->getType();
+      if (OrigTy->isVectorTy() != (VFParam.ParamKind == VFParamKind::Vector)) {
+        LLVM_DEBUG(dbgs() << DEBUG_TYPE << ": Will not replace: " << ScalarName
+                          << ". Wrong type at index " << VFParam.ParamPos
+                          << ": " << *OrigTy << "\n");
+        return false;
+      }
+    }
+  }
+
   FunctionType *VectorFTy = VFABI::createFunctionType(*OptInfo, ScalarFTy);
   if (!VectorFTy)
     return false;
 
   Function *TLIFunc = getTLIFunction(I.getModule(), VectorFTy,
                                      VD->getVectorFnName(), FuncToReplace);
+
   replaceWithTLIFunction(I, *OptInfo, TLIFunc);
   LLVM_DEBUG(dbgs() << DEBUG_TYPE << ": Replaced call to `" << ScalarName
                     << "` with call to `" << TLIFunc->getName() << "`.\n");
@@ -220,6 +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/CMakeLists.txt

@@ -1,6 +1,7 @@
 set(LLVM_LINK_COMPONENTS
   Analysis
   AsmParser
+  CodeGen
   Core
   Passes
   Support
@@ -40,6 +41,7 @@ set(ANALYSIS_TEST_SOURCES
   PluginInlineAdvisorAnalysisTest.cpp
   PluginInlineOrderAnalysisTest.cpp
   ProfileSummaryInfoTest.cpp
+  ReplaceWithVecLibTest.cpp
   ScalarEvolutionTest.cpp
   VectorFunctionABITest.cpp
   SparsePropagation.cpp

llvm/unittests/Analysis/ReplaceWithVecLibTest.cpp

@@ -0,0 +1,113 @@
+//===--- ReplaceWithVecLibTest.cpp - replace-with-veclib unit tests -------===//
+//
+// 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/CodeGen/ReplaceWithVeclib.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Passes/PassBuilder.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+/// NOTE: Assertions must be enabled for these tests to run.
+#ifndef NDEBUG
+
+namespace {
+
+static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
+  SMDiagnostic Err;
+  std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
+  if (!Mod)
+    Err.print("ReplaceWithVecLibTest", errs());
+  return Mod;
+}
+
+/// Runs ReplaceWithVecLib with different TLIIs that have custom VecDescs. This
+/// allows checking that the pass won't crash when the function to replace (from
+/// 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 any trailing '\n'
+    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).
+  ///
+  /// \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());
+    TLII.addVectorizableFunctions({VD});
+    FunctionAnalysisManager FAM;
+    FAM.registerPass([&TLII]() { return TargetLibraryAnalysis(TLII); });
+
+    // Register and run the pass on the 'foo' function from the input IR.
+    FunctionPassManager FPM;
+    FPM.addPass(ReplaceWithVeclib());
+    std::unique_ptr<Module> M = parseIR(Ctx, IR);
+    PassBuilder PB;
+    PB.registerFunctionAnalyses(FAM);
+
+    // Enable debugging and capture std error
+    llvm::DebugFlag = true;
+    testing::internal::CaptureStderr();
+    FPM.run(*M->getFunction("foo"), FAM);
+    return getLastLine(testing::internal::GetCapturedStderr());
+  }
+};
+
+} // end anonymous namespace
+
+static const char *IR = R"IR(
+define <vscale x 4 x float> @foo(<vscale x 4 x float> %in){
+  %call = call <vscale x 4 x float> @llvm.powi.f32.i32(<vscale x 4 x float> %in, i32 3)
+  ret <vscale x 4 x float> %call
+}
+
+declare <vscale x 4 x float> @llvm.powi.f32.i32(<vscale x 4 x float>, i32) #0
+)IR";
+
+// The VFABI prefix in TLI describes signature which is matching the powi
+// intrinsic declaration.
+TEST_F(ReplaceWithVecLibTest, TestValidMapping) {
+  VecDesc CorrectVD = {"llvm.powi.f32.i32", "_ZGVsMxvu_powi",
+                       ElementCount::getScalable(4), /*Masked*/ true,
+                       "_ZGVsMxvu"};
+  EXPECT_EQ(run(CorrectVD, IR),
+            "Instructions replaced with vector libraries: 1");
+}
+
+// The VFABI prefix in TLI describes signature which is not matching the powi
+// intrinsic declaration.
+TEST_F(ReplaceWithVecLibTest, TestInvalidMapping) {
+  VecDesc IncorrectVD = {"llvm.powi.f32.i32", "_ZGVsMxvv_powi",
+                         ElementCount::getScalable(4), /*Masked*/ true,
+                         "_ZGVsMxvv"};
+  EXPECT_EQ(run(IncorrectVD, IR),
+            "replace-with-veclib: Will not replace: llvm.powi.f32.i32. Wrong "
+            "type at index 1: i32");
+}
+#endif