[inductor] enable Intel Compiler(icx-cl) for inductor windows (pytorc…

…h#134772)

This PR is enable Intel Compiler (`icx-cl`) for Windows inductor, likes previous PR: pytorch#134444 which enable clang.

Changes:
1. Fix icx-cl crash by wrong decode args, the right decode should be "utf-8".
2. Add intel compiler check, and intel compiler Windows drivers check(icx-cl).
3. Add Intel compiler openmp args config.
4. Add intel compiler openmp binary preload.

For intel compiler openmp binary path:
<img width="788" alt="image" src="https://github.com/user-attachments/assets/54c76356-018d-4bef-a9b7-0ea150fd7aba">

For performance, Intel compiler(`icx-cl`) is much better performance than MSVC(`cl`):
<img width="875" alt="image" src="https://github.com/user-attachments/assets/67865faf-b1de-4535-917a-486b72527204">

Append `clang-cl` performance data:
<img width="821" alt="image" src="https://github.com/user-attachments/assets/476f4568-bf58-457f-b73d-4e57f49be384">

Pull Request resolved: pytorch#134772
Approved by: https://github.com/jgong5, https://github.com/jansel

torch/_inductor/cpp_builder.py

@@ -58,7 +58,7 @@ def use_global_cache() -> bool:
 _IS_MACOS = sys.platform.startswith("darwin")
 _IS_WINDOWS = sys.platform == "win32"
 
-SUBPROCESS_DECODE_ARGS = ("oem",) if _IS_WINDOWS else ()
+SUBPROCESS_DECODE_ARGS = ("utf-8",) if _IS_WINDOWS else ()
 
 log = logging.getLogger(__name__)
 
@@ -198,6 +198,33 @@ def _is_msvc_cl(cpp_compiler: str) -> bool:
     return False
 
 
+@functools.lru_cache(None)
+def _is_intel_compiler(cpp_compiler: str) -> bool:
+    try:
+        output_msg = (
+            subprocess.check_output(
+                [cpp_compiler, "--version"], stderr=subprocess.DEVNULL
+            )
+            .strip()
+            .decode(*SUBPROCESS_DECODE_ARGS)
+        )
+        is_intel_compiler = "Intel" in output_msg.splitlines()[0]
+        if is_intel_compiler:
+            if _IS_WINDOWS:
+                if re.search(r"((icx$)|(icx-cc$))", cpp_compiler):
+                    raise RuntimeError(
+                        "Please use icx-cl, due to torch.compile only support MSVC-like CLI (compiler flags syntax)."
+                    )
+        return is_intel_compiler
+    except FileNotFoundError as exc:
+        return False
+    except subprocess.SubprocessError:
+        # --version args not support.
+        return False
+
+    return False
+
+
 @functools.lru_cache(None)
 def is_gcc() -> bool:
     return _is_gcc(get_cpp_compiler())
@@ -208,6 +235,11 @@ def is_clang() -> bool:
     return _is_clang(get_cpp_compiler())
 
 
+@functools.lru_cache(None)
+def is_intel_compiler() -> bool:
+    return _is_intel_compiler(get_cpp_compiler())
+
+
 @functools.lru_cache(None)
 def is_apple_clang() -> bool:
     return _is_apple_clang(get_cpp_compiler())
@@ -798,6 +830,20 @@ def perload_clang_libomp_win(cpp_compiler: str, omp_name: str) -> None:
         pass
 
 
+@functools.lru_cache(None)
+def perload_icx_libomp_win(cpp_compiler: str) -> None:
+    try:
+        output = subprocess.check_output(
+            [cpp_compiler, "-print-file-name=libiomp5md.dll"], stderr=subprocess.DEVNULL
+        ).decode(*SUBPROCESS_DECODE_ARGS)
+        omp_path = output.rstrip()
+        if os.path.isfile(omp_path):
+            os.environ["KMP_DUPLICATE_LIB_OK"] = "TRUE"
+            omp_module = cdll.LoadLibrary(omp_path)
+    except subprocess.SubprocessError:
+        pass
+
+
 def _get_openmp_args(
     cpp_compiler: str,
 ) -> Tuple[List[str], List[str], List[str], List[str], List[str], List[str]]:
@@ -854,10 +900,28 @@ def _get_openmp_args(
         # if openmp is still not available, we let the compiler to have a try,
         # and raise error together with instructions at compilation error later
     elif _IS_WINDOWS:
+        """
+        On Windows, `clang` and `icx` have their specific openmp implenmention.
+        And the openmp lib is in compiler's some sub-directory.
+        For dynamic library(DLL) load, the Windows native APIs are `LoadLibraryA` and `LoadLibraryExA`, and their search
+        dependencies have some rules:
+        https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexa#searching-for-dlls-and-dependencies
+        In some case, the rules may not include compiler's sub-directories.
+        So, it can't search and load compiler's openmp library correctly.
+        And then, the whole application would be broken.
+
+        To avoid the openmp load failed, we can automatic locate the openmp binary and preload it.
+        1. For clang, the function is `perload_clang_libomp_win`.
+        2. For icx, the function is `perload_icx_libomp_win`.
+        """
         if _is_clang(cpp_compiler):
             cflags.append("openmp")
             libs.append("libomp")
             perload_clang_libomp_win(cpp_compiler, "libomp.dll")
+        elif _is_intel_compiler(cpp_compiler):
+            cflags.append("Qiopenmp")
+            libs.append("libiomp5md")
+            perload_icx_libomp_win(cpp_compiler)
         else:
             # /openmp, /openmp:llvm
             # llvm on Windows, new openmp: https://devblogs.microsoft.com/cppblog/msvc-openmp-update/