[MLIR][LLVM] Fix CallOp asm parser for attr-dict (#74372)

Currently the parser & printer of `CallOp` do not match when both
varargs and attr-dict are present (round tripping is broken). This fixes
the parser so that it conforms to the written asm format in the
comments.

Author: zyx-billy

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

@@ -1219,8 +1219,7 @@ ParseResult CallOp::parse(OpAsmParser &parser, OperationState &result) {
       return failure();
 
   // Parse the function arguments.
-  if (parser.parseOperandList(operands, OpAsmParser::Delimiter::Paren) ||
-      parser.parseOptionalAttrDict(result.attributes))
+  if (parser.parseOperandList(operands, OpAsmParser::Delimiter::Paren))
     return failure();
 
   bool isVarArg = parser.parseOptionalKeyword("vararg").succeeded();
@@ -1232,6 +1231,9 @@ ParseResult CallOp::parse(OpAsmParser &parser, OperationState &result) {
       return failure();
   }
 
+  if (parser.parseOptionalAttrDict(result.attributes))
+    return failure();
+
   // Parse the trailing type list and resolve the operands.
   return parseCallTypeAndResolveOperands(parser, result, isDirect, operands);
 }

mlir/test/Dialect/LLVMIR/roundtrip.mlir

@@ -73,11 +73,15 @@ func.func @ops(%arg0: i32, %arg1: f32,
 
 // Variadic calls
 // CHECK:  llvm.call @vararg_func(%arg0, %arg0) vararg(!llvm.func<void (i32, ...)>) : (i32, i32) -> ()
+// CHECK:  llvm.call @vararg_func(%arg0, %arg0) vararg(!llvm.func<void (i32, ...)>) {fastmathFlags = #llvm.fastmath<fast>} : (i32, i32) -> ()
 // CHECK:  %[[VARIADIC_FUNC:.*]] = llvm.mlir.addressof @vararg_func : !llvm.ptr
 // CHECK:  llvm.call %[[VARIADIC_FUNC]](%[[I32]], %[[I32]]) vararg(!llvm.func<void (i32, ...)>) : !llvm.ptr, (i32, i32) -> ()
+// CHECK:  llvm.call %[[VARIADIC_FUNC]](%[[I32]], %[[I32]]) vararg(!llvm.func<void (i32, ...)>) {fastmathFlags = #llvm.fastmath<fast>} : !llvm.ptr, (i32, i32) -> ()
   llvm.call @vararg_func(%arg0, %arg0) vararg(!llvm.func<void (i32, ...)>) : (i32, i32) -> ()
+  llvm.call @vararg_func(%arg0, %arg0) vararg(!llvm.func<void (i32, ...)>) {fastmathFlags = #llvm.fastmath<fast>} : (i32, i32) -> ()
   %variadic_func = llvm.mlir.addressof @vararg_func : !llvm.ptr
   llvm.call %variadic_func(%arg0, %arg0) vararg(!llvm.func<void (i32, ...)>) : !llvm.ptr, (i32, i32) -> ()
+  llvm.call %variadic_func(%arg0, %arg0) vararg(!llvm.func<void (i32, ...)>) {fastmathFlags = #llvm.fastmath<fast>} : !llvm.ptr, (i32, i32) -> ()
 
 // Terminator operations and their successors.
 //

mlir/test/Target/LLVMIR/llvmir.mlir

@@ -1223,19 +1223,23 @@ llvm.func @dereferenceableornullattr_ret_decl() -> (!llvm.ptr {llvm.dereferencea
 llvm.func @inregattr_ret_decl() -> (!llvm.ptr {llvm.inreg})
 
 // CHECK-LABEL: @varargs(...)
-llvm.func @varargs(...)
+llvm.func @varargs(...) -> f32
 
 // CHECK-LABEL: define void @varargs_call
 llvm.func @varargs_call(%arg0 : i32) {
-// CHECK:  call void (...) @varargs(i32 %{{.*}})
-  llvm.call @varargs(%arg0) vararg(!llvm.func<void (...)>) : (i32) -> ()
+// CHECK:  call float (...) @varargs(i32 %{{.*}})
+// CHECK:  call nnan float (...) @varargs(i32 %{{.*}})
+  llvm.call @varargs(%arg0) vararg(!llvm.func<f32 (...)>) : (i32) -> (f32)
+  llvm.call @varargs(%arg0) vararg(!llvm.func<f32 (...)>) {fastmathFlags = #llvm.fastmath<nnan>} : (i32) -> (f32)
   llvm.return
 }
 
 // CHECK-LABEL: define void @indirect_varargs_call(ptr %0, i32 %1)
 llvm.func @indirect_varargs_call(%arg0 : !llvm.ptr, %arg1 : i32) {
-// CHECK:  call void (...) %0(i32 %1)
-  llvm.call %arg0(%arg1) vararg(!llvm.func<void (...)>) : !llvm.ptr, (i32) -> ()
+// CHECK:  call float (...) %0(i32 %1)
+// CHECK:  call nnan float (...) %0(i32 %1)
+  llvm.call %arg0(%arg1) vararg(!llvm.func<f32 (...)>) : !llvm.ptr, (i32) -> (f32)
+  llvm.call %arg0(%arg1) vararg(!llvm.func<f32 (...)>) {fastmathFlags = #llvm.fastmath<nnan>} : !llvm.ptr, (i32) -> (f32)
   llvm.return
 }