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Chrome continues to use MSVC on Windows because it generates better code than clang. So, MSVC is the worst compiler, except for the alternatives?
by brucedawson 10y ago
Chrome continues to use MSVC on Windows because it generates better code than clang. So, MSVC is the worst compiler, except for the alternatives?
- obl 10y agoWould appreciate a reference on that if you have it handy. Is this more of a whole program measured X% regression on some perf benchs, or specific target cases where the codegen is notably worse ?
- brucedawson 10y agocrbug.com/457078 talks about binary size in clang-cl versus VC++. On x86 builds clang-cl produces ~14% larger binaries. On x64 builds it produces ~3.5% smaller binaries. My recent changes have made the comparison tougher for clang-cl by making the VC++ binaries smaller :-)
- brucedawson 10y agoI should probably take back my claim because I can't find the evidence to back it up and I might actually be wrong. I thought I remembered that there were some important cases where VC++ generated better code for Chrome, and some binary size advantages, but I can't find my references.
- Joky 10y agoI believe I read that it is rather that clang is (was?) not feature complete (until recently at least) for debugging in MSVC. Support for PDB/Codeview is very recent in clang, and I'm not sure it is complete yet.