rocmPackages.llvm: backport select-ptr combine so llvm-22 sdag fix ap… (#543676)

pkgs/development/rocm-modules/llvm/default.nix

@@ -293,7 +293,29 @@ let
 in
 overrideLlvmPackagesRocm (s: {
   libllvm = (s.prev.libllvm.override { }).overrideAttrs (old: {
-    patches = old.patches ++ [
+    patches = [
+      # Backport select ptr combine fixes so our LLVM 22 sdag fix backport can apply
+      (fetchpatch {
+        name = "amdgpu-add-baseline-load-select-ptr-combine-test.patch";
+        url = "https://github.com/llvm/llvm-project/commit/ac27b2455ad7c89cc1f928de7beb05933a035031.patch";
+        relative = "llvm";
+        hash = "sha256-1mine1h/oqnn2tKDYW4FntyZXu/foyifrKGkqKOHrPg=";
+      })
+      (fetchpatch {
+        name = "amdgpu-fix-treating-divergent-loads-as-uniform.patch";
+        url = "https://github.com/llvm/llvm-project/commit/d3c3c6bab5df051d9db12ea96add2211df9d81be.patch";
+        relative = "llvm";
+        hash = "sha256-9VB77d4d+nwX8s+JBq1PXmbmqT7oD6lRC0uDIrTgjjo=";
+      })
+      (fetchpatch {
+        name = "dag-allow-select-ptr-combine-for-non-0-address-spaces.patch";
+        url = "https://github.com/llvm/llvm-project/commit/0e1cb2de90aafa1d5dbd46fc9e6c4e743700fa8b.patch";
+        relative = "llvm";
+        hash = "sha256-6Pj3pRESaho60YhXWwaQxEKteSuziZseeT4FbZqZANk=";
+      })
+    ]
+    ++ old.patches
+    ++ [
       ./perf-increase-namestring-size.patch
       # v64i8 shuffle lowering inf loop on VBMI targets, hangs whisper-cpp etc
       # https://github.com/NixOS/nixpkgs/issues/497745