[Clang][AMDGPU] Use size_t to compare with npos

[jsji]

Fix error

llvm\clang\tools\amdgpu-arch\AMDGPUArchByHIP.cpp(102,29): error: result of comparison of constant 18446744073709551615 with expression of type 'unsigned int' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
102 | StringRef VerStr = (Pos == StringRef::npos) ? S : S.substr(Pos + 1);

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

@llvm/pr-subscribers-clang

Author: Jinsong Ji (jsji)

Changes

Fix error

llvm\clang\tools\amdgpu-arch\AMDGPUArchByHIP.cpp(102,29): error: result of comparison of constant 18446744073709551615 with expression of type 'unsigned int' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
102 | StringRef VerStr = (Pos == StringRef::npos) ? S : S.substr(Pos + 1);

---

Full diff: https://github.com/llvm/llvm-project/pull/132868.diff

1 Files Affected:

• (modified) clang/tools/amdgpu-arch/AMDGPUArchByHIP.cpp (+1-1)

diff --git a/clang/tools/amdgpu-arch/AMDGPUArchByHIP.cpp b/clang/tools/amdgpu-arch/AMDGPUArchByHIP.cpp
index 4803f83f55ac7..02431bf909d6d 100644
--- a/clang/tools/amdgpu-arch/AMDGPUArchByHIP.cpp
+++ b/clang/tools/amdgpu-arch/AMDGPUArchByHIP.cpp
@@ -98,7 +98,7 @@ static std::vector<std::string> getSearchPaths() {
 // Custom comparison function for dll name
 static bool compareVersions(StringRef A, StringRef B) {
   auto ParseVersion = [](StringRef S) -> VersionTuple {
-    unsigned Pos = S.find_last_of('_');
+    size_t Pos = S.find_last_of('_');
     StringRef VerStr = (Pos == StringRef::npos) ? S : S.substr(Pos + 1);
     VersionTuple Vt;
     (void)Vt.tryParse(VerStr);

[yxsamliu]

Thanks for fixing this.