Update compiletests CUDA-finding code.

Remove some CUDA 11 references, add some CUDA 13 references. Also
separate the Unix and Windows code a little more.

Author: nnethercote

crates/nvvm/src/lib.rs

@@ -312,8 +312,10 @@ pub enum NvvmArch {
     /// This default value of 7.5 corresponds to Turing and later devices. We default to this
     /// because it is the minimum supported by CUDA 13.0 while being in the middle of the range
     /// supported by CUDA 12.x.
-    // WARNING: If you change the default, consider updating the `--target-arch` values used for
-    // compiletests in `ci_linux.yml` and `.github/workflows/ci_{linux,windows}.yml`.
+    // WARNING: If you change the default, consider updating:
+    // - The `--target-arch` values used for compiletests in `ci_linux.yml` and
+    //   `.github/workflows/ci_{linux,windows}.yml`.
+    // - The CUDA versions used in `setup_cuda_environment` in `compiletests`.
     #[default]
     Compute75,
     Compute80,

tests/compiletests/src/main.rs

@@ -576,30 +576,41 @@ fn setup_cuda_environment() {
     // Set library path to include CUDA NVVM libraries
     let lib_path_var = dylib_path_envvar();
 
-    // Try to find CUDA installation
-    let cuda_paths = vec![
-        "/usr/local/cuda/nvvm/lib64",
-        "/usr/local/cuda-12/nvvm/lib64",
-        "/usr/local/cuda-11/nvvm/lib64",
-        "C:\\Program Files\\NVIDIA GPU Computing Toolkit\\CUDA\\v12.8\\nvvm\\lib\\x64",
-        "C:\\Program Files\\NVIDIA GPU Computing Toolkit\\CUDA\\v12.0\\nvvm\\lib\\x64",
-        "C:\\Program Files\\NVIDIA GPU Computing Toolkit\\CUDA\\v11.8\\nvvm\\lib\\x64",
-    ];
-
     let mut found_cuda_paths = Vec::new();
 
     // Check CUDA_PATH environment variable
     if let Ok(cuda_path) = env::var("CUDA_PATH") {
-        let nvvm_path = Path::new(&cuda_path).join("nvvm").join("lib64");
-        if nvvm_path.exists() {
-            found_cuda_paths.push(nvvm_path.to_string_lossy().to_string());
+        #[cfg(unix)]
+        {
+            let nvvm_path = Path::new(&cuda_path).join("nvvm").join("lib64");
+            if nvvm_path.exists() {
+                found_cuda_paths.push(nvvm_path.to_string_lossy().to_string());
+            }
         }
-        let nvvm_path_win = Path::new(&cuda_path).join("nvvm").join("lib").join("x64");
-        if nvvm_path_win.exists() {
-            found_cuda_paths.push(nvvm_path_win.to_string_lossy().to_string());
+        #[cfg(windows)]
+        {
+            let nvvm_path = Path::new(&cuda_path).join("nvvm").join("lib").join("x64");
+            if nvvm_path.exists() {
+                found_cuda_paths.push(nvvm_path.to_string_lossy().to_string());
+            }
         }
     }
 
+    // Try to find CUDA installation
+    #[cfg(unix)]
+    let cuda_paths = vec![
+        "/usr/local/cuda/nvvm/lib64",
+        "/usr/local/cuda-13/nvvm/lib64",
+        "/usr/local/cuda-12/nvvm/lib64",
+    ];
+    #[cfg(windows)]
+    let cuda_paths = vec![
+        "C:\\Program Files\\NVIDIA GPU Computing Toolkit\\CUDA\\v13.0\\nvvm\\lib\\x64",
+        "C:\\Program Files\\NVIDIA GPU Computing Toolkit\\CUDA\\v12.9\\nvvm\\lib\\x64",
+        "C:\\Program Files\\NVIDIA GPU Computing Toolkit\\CUDA\\v12.8\\nvvm\\lib\\x64",
+        "C:\\Program Files\\NVIDIA GPU Computing Toolkit\\CUDA\\v12.0\\nvvm\\lib\\x64",
+    ];
+
     // Check standard paths
     for path in &cuda_paths {
         if Path::new(path).exists() {