[llvm-dev] Potential problem with -Wunreachable-code

Ian Collins via llvm-dev llvm-dev at lists.llvm.org
Thu Nov 21 19:28:54 PST 2019

Hello, hopefully this is the correct place to ask this...

We use distcc with clang++ and I have recently added -Wunreachable-code 
to our set of warnings.  The problem I am seeing is the compile fails 
with (valid) unreachable code warnings on the slave, but passes (no 
warning) locally.  All machines have the same compiler version

clang version 8.0.1-svn369350-1~exp1~20190820121219.79 (branches/release_80)

Distcc takes the compile line, removes -o <output> and replaces it with 
-E and sends the preprocessed result to the slave where it is compiled 
without any -I, -isystem or -D options. Generating the preprocessed 
output and compiling it locally finds the warnings.  I'm concerned that 
we are seeing a different result for the output of -E and the standard 

The compiler options are:



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