src/third_party/llvm-project/clang/test/CodeGen/2004-02-20-Builtins.c

// RUN: %clang_cc1  %s -emit-llvm -o - | FileCheck %s
double sqrt(double x);

// CHECK-LABEL: @zsqrtxxx
// CHECK-NOT: builtin
void zsqrtxxx(float num) {
   num = sqrt(num);
}