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Viewing changes to debian/patches/lto-gcc-4.9.diff

  • Committer: Package Import Robot
  • Author(s): Martin Quinson
  • Date: 2014-07-05 00:20:25 UTC
  • Revision ID: package-import@ubuntu.com-20140705002025-x0d5sceaovd5jhpw
Tags: 3.11.1-7
* Disable LTO on all non-AMD architectures to circumvent a seemingly
  bug in gcc 4.9.
* Re-enable parallel builds now that LTO issues are (hopefully) fixed.

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debian/patches/lto-gcc-4.9.diff
 
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The LTO optimization seems to be somehow broken on most architectures.
 
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The funny thing is that it breaks only sometimes, even if we are not
 
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build in parallel. For more information, please see:
 
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https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=753134
 
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As an answer, we disable LTO for all non-AMD architectures. Simgrid is
 
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not crucial to those architectures anyway.
 
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---
 
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 buildtools/Cmake/Flags.cmake |    6 +++++-
 
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 1 file changed, 5 insertions(+), 1 deletion(-)
 
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Index: b/buildtools/Cmake/Flags.cmake
 
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===================================================================
 
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--- a/buildtools/Cmake/Flags.cmake
 
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+++ b/buildtools/Cmake/Flags.cmake
 
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@@ -37,7 +37,11 @@ if(enable_compile_optimizations)
 
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     else()    
 
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       # On non-windows, 4.6 is enough for that
 
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       if(COMPILER_C_VERSION_MAJOR_MINOR STRGREATER "4.5" AND LINKER_VERSION STRGREATER "2.22")
 
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-        set(optCFLAGS "${optCFLAGS} -flto ")
 
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+       if(NOT CMAKE_SYSTEM_PROCESSOR MATCHES ".86|AMD64|amd64" AND COMPILER_C_VERSION_MAJOR_MINOR STREQUAL "4.9")
 
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+         message(STATUS "Disable LTO on non-AMD architectures as gcc 4.9 seems to be broken here (see #753134 on Debian)")
 
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+       else()
 
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+          set(optCFLAGS "${optCFLAGS} -flto ")
 
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+       endif()
 
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       endif()
 
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     endif()
 
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   endif()