[llvm] [TLI] Pass replace-with-veclib works with Scalable Vectors. (PR #73642)

[Paschalis Mpeis via llvm-commits]

================
@@ -38,138 +42,152 @@ STATISTIC(NumTLIFuncDeclAdded,
 STATISTIC(NumFuncUsedAdded,
           "Number of functions added to `llvm.compiler.used`");
 
-static bool replaceWithTLIFunction(CallInst &CI, const StringRef TLIName) {
-  Module *M = CI.getModule();
-
-  Function *OldFunc = CI.getCalledFunction();
-
-  // Check if the vector library function is already declared in this module,
-  // otherwise insert it.
+/// Returns a vector Function that it adds to the Module \p M. When an \p
+/// ScalarFunc is not null, it copies its attributes to the newly created
+/// Function.
+Function *getTLIFunction(Module *M, FunctionType *VectorFTy,
+                         Function *ScalarFunc, const StringRef TLIName) {
   Function *TLIFunc = M->getFunction(TLIName);
   if (!TLIFunc) {
-    TLIFunc = Function::Create(OldFunc->getFunctionType(),
-                               Function::ExternalLinkage, TLIName, *M);
-    TLIFunc->copyAttributesFrom(OldFunc);
+    TLIFunc =
+        Function::Create(VectorFTy, Function::ExternalLinkage, TLIName, *M);
+    if (ScalarFunc)
+      TLIFunc->copyAttributesFrom(ScalarFunc);
 
     LLVM_DEBUG(dbgs() << DEBUG_TYPE << ": Added vector library function `"
                       << TLIName << "` of type `" << *(TLIFunc->getType())
                       << "` to module.\n");
 
     ++NumTLIFuncDeclAdded;
-
-    // Add the freshly created function to llvm.compiler.used,
-    // similar to as it is done in InjectTLIMappings
+    // Add the freshly created function to llvm.compiler.used, similar to as it
+    // is done in InjectTLIMappings.
     appendToCompilerUsed(*M, {TLIFunc});
-
     LLVM_DEBUG(dbgs() << DEBUG_TYPE << ": Adding `" << TLIName
                       << "` to `@llvm.compiler.used`.\n");
     ++NumFuncUsedAdded;
   }
+  return TLIFunc;
+}
 
-  // Replace the call to the vector intrinsic with a call
-  // to the corresponding function from the vector library.
+/// Replace the call to the vector intrinsic ( \p FuncToReplace ) with a call to
+/// the corresponding function from the vector library ( \p TLIFunc ).
+static void replaceWithTLIFunction(CallInst &CI, VFInfo &Info,
+                                   Function *TLIVecFunc) {
   IRBuilder<> IRBuilder(&CI);
   SmallVector<Value *> Args(CI.args());
+  if (auto OptMaskpos = Info.getParamIndexForOptionalMask()) {
+    if (Args.size() == TLIVecFunc->getFunctionType()->getNumParams())
+      static_assert(true && "mask was already in place");
----------------
paschalis-mpeis wrote:

> To me looks like there is no way to handle masked vector intrinsics passed as input to this pass, as you are not able to distinguish if the vector of i1 is a mask or just a regular argument.

Technically we can distinguish between i1 masks and regular arguments using `Info.Shape.Parameters`.
But, I also think that it may not reach here with a mask already in place.
I wasn't sure though, which is why I've added the assertion.

https://github.com/llvm/llvm-project/pull/73642