[PATCH] D20454: Eliminate unnecessary file access checks in Clang driver on Windows

[Adrian McCarthy via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL270226: Eliminate unnecessary file access checks in Clang driver on Windows (authored by amccarth).

Changed prior to commit:
  http://reviews.llvm.org/D20454?vs=57872&id=57936#toc

Repository:
  rL LLVM

http://reviews.llvm.org/D20454

Files:
  cfe/trunk/lib/Driver/MSVCToolChain.cpp

Index: cfe/trunk/lib/Driver/MSVCToolChain.cpp
===================================================================
--- cfe/trunk/lib/Driver/MSVCToolChain.cpp
+++ cfe/trunk/lib/Driver/MSVCToolChain.cpp
@@ -408,7 +408,10 @@
 
         SmallString<128> FilePath(PathSegment);
         llvm::sys::path::append(FilePath, "cl.exe");
-        if (llvm::sys::fs::can_execute(FilePath.c_str()) &&
+        // Checking if cl.exe exists is a small optimization over calling
+        // can_execute, which really only checks for existence but will also do
+        // extra checks for cl.exe.exe.  These add up when walking a long path.
+        if (llvm::sys::fs::exists(FilePath.c_str()) &&
             !llvm::sys::fs::equivalent(FilePath.c_str(), clangProgramPath)) {
           // If we found it on the PATH, use it exactly as is with no
           // modifications.


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