[MLIR][LLVM] Allow inlining LLVM functions with branch weights.

[definelicht]

Summary

This does not require any special handling and can just be dropped.

[gysit]

LGTM!

[definelicht]

Superseded by https://reviews.llvm.org/D144104.

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

struct LLVMInlinerInterface : public DialectInlinerInterface {
   }
 
 private:
   /// Returns true if all attributes of `callOp` are handled during inlining.
   [[nodiscard]] static bool isLegalToInlineCallAttributes(LLVM::CallOp callOp) {
     return all_of(callOp.getAttributeNames(), [&](StringRef attrName) {
       return llvm::StringSwitch<bool>(attrName)
           // TODO: Propagate and update branch weights.
-          .Case("branch_weights", !callOp.getBranchWeights())
+          .Case("branch_weights", true)
           .Case("callee", true)
           .Case("fastmathFlags", true)
           .Default(false);
     });
   }
 
   /// Returns true if all attributes of `funcOp` are handled during inlining.
   [[nodiscard]] static bool

mlir/test/Dialect/LLVMIR/inlining.mlir

llvm.func internal fastcc @callee() -> (i32) attributes { function_entry_count = 42 : i64, dso_local } {
   llvm.return %0 : i32
 }
 
 // CHECK-LABEL: llvm.func @caller
 // CHECK-NEXT: %[[CST:.+]] = llvm.mlir.constant
 // CHECK-NEXT: llvm.return %[[CST]]
 llvm.func @caller() -> (i32) {
   // Include all call attributes that don't prevent inlining.
-  %0 = llvm.call @callee() { fastmathFlags = #llvm.fastmath<nnan, ninf> } : () -> (i32)
+  %0 = llvm.call @callee() { fastmathFlags = #llvm.fastmath<nnan, ninf>, branch_weights = dense<42> : vector<1xi32> } : () -> (i32)
   llvm.return %0 : i32
 }
 
 // -----
 
 llvm.func @foo() -> (i32) attributes { passthrough = ["noinline"] } {
   %0 = llvm.mlir.constant(0 : i32) : i32
   llvm.return %0 : i32

 // CHECK-NEXT: return
 llvm.func @caller(%ptr : !llvm.ptr) -> (!llvm.ptr) {
   %0 = llvm.call @callee(%ptr) : (!llvm.ptr) -> (!llvm.ptr)
   llvm.return %0 : !llvm.ptr
 }
 
 // -----
 
-llvm.func @callee() {
-  llvm.return
-}
-
-// CHECK-LABEL: llvm.func @caller
-// CHECK-NEXT: llvm.call @callee
-// CHECK-NEXT: llvm.return
-llvm.func @caller() {
-  llvm.call @callee() { branch_weights = dense<42> : vector<1xi32> } : () -> ()
-  llvm.return
-}
-
-// -----
-
 llvm.func @static_alloca() -> f32 {
   %0 = llvm.mlir.constant(4 : i32) : i32
   %1 = llvm.alloca %0 x f32 : (i32) -> !llvm.ptr
   %2 = llvm.load %1 : !llvm.ptr -> f32
   llvm.return %2 : f32
 }
 
 llvm.func @dynamic_alloca(%size : i32) -> f32 {