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| -rw-r--r-- | docs/tools/clang.pod | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/docs/tools/clang.pod b/docs/tools/clang.pod index 9628d473b7..d2394a84a5 100644 --- a/docs/tools/clang.pod +++ b/docs/tools/clang.pod @@ -7,7 +7,7 @@ clang - the Clang C, C++, and Objective-C compiler =head1 SYNOPSIS B<clang> [B<-c>|B<-S>|B<-E>] B<-std=>I<standard> B<-g> - [B<-O0>|B<-O1>|B<-O2>|B<-Os>|B<-Oz>|B<-O3>|B<-O4>] + [B<-O0>|B<-O1>|B<-O2>|B<-Os>|B<-Oz>|B<-O3>|B<-Ofast>|B<-O4>] B<-W>I<warnings...> B<-pedantic> B<-I>I<dir...> B<-L>I<dir...> B<-D>I<macro[=defn]> @@ -263,7 +263,7 @@ may not exist on earlier ones. =over -=item B<-O0> B<-O1> B<-O2> B<-Os> B<-Oz> B<-O3> B<-O4> +=item B<-O0> B<-O1> B<-O2> B<-Os> B<-Oz> B<-O3> B<-Ofast> B<-O4> Specify which optimization level to use. B<-O0> means "no optimization": this level compiles the fastest and generates the most debuggable code. B<-O2> is a @@ -271,7 +271,9 @@ moderate level of optimization which enables most optimizations. B<-Os> is like B<-O2> with extra optimizations to reduce code size. B<-Oz> is like B<-Os> (and thus B<-O2>), but reduces code size further. B<-O3> is like B<-O2>, except that it enables optimizations that take longer to perform or that may -generate larger code (in an attempt to make the program run faster). On +generate larger code (in an attempt to make the program run faster). +B<-Ofast> enables all the optimizations from B<-O3> along with other aggressive +optimizations that may violate strict compliance with language standards. On supported platforms, B<-O4> enables link-time optimization; object files are stored in the LLVM bitcode file format and whole program optimization is done at link time. B<-O1> is somewhere between B<-O0> and B<-O2>. |