vsk added a comment. I discussed this bug with Argyrios off-list, who lgtm'd on the condition that it doesn't introduce a performance regression. He suggested preprocessing Cocoa.h to stress the patch. After running a stabilization script, I used this command to stress RelNoAsserts builds of clang both with and without this patch.
for I in $(seq 1 100); do time $CC -F /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk/System/Library/Frameworks -E Cocoa.h -o /dev/null; done The results are basically in the noise (link to raw data: https://ghostbin.com/paste/r6cyh): | Compiler | **Unpatched** TOT | **Patched** TOT | | Avg. wall time (s) | 0.21709 | 0.21608 | | Std. deviation | 0.02101 | 0.02219 | I also made sure that the preprocessed sources emitted by the two compilers are the same. http://reviews.llvm.org/D20401 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
