optional-optimization-parameters-for-icc.md

Optional optimization parameters for ICC

Notes

• The following parameters are for Windows platform only, if you are using Linux, you need change a little bit.
• ICC does NOT support "/utf-8", use "-Qoption,cpp,--unicode_source_kind,"UTF-8"" instead.

Configuration file

<path_to_qt_source_code_directory>\qtbase\mkspecs\win32-icc\qmake.conf

For example:

C:\Qt\src\qtbase\mkspecs\win32-icc\qmake.conf

Optimization parameters

1. Add "-Ob2 -Oi -Ot -GT -Qftz -Qopt-matmul -Qunroll -Qparallel -Quse-intel-optimized-headers" to "QMAKE_CFLAGS_OPTIMIZE_FULL":

   QMAKE_CFLAGS_OPTIMIZE_FULL = -O3 -Ob2 -Oi -Ot -GT -Qftz -Qopt-matmul -Qunroll -Qparallel -Quse-intel-optimized-headers
   

2. Add "QMAKE_CFLAGS_RELEASE" and "QMAKE_CFLAGS_RELEASE_WITH_DEBUGINFO" below "QMAKE_CFLAGS_OPTIMIZE_FULL":

   QMAKE_CFLAGS_RELEASE = $$QMAKE_CFLAGS_OPTIMIZE_FULL -MD
   QMAKE_CFLAGS_RELEASE_WITH_DEBUGINFO = $$QMAKE_CFLAGS_OPTIMIZE_FULL -Zi -MD
   

NOTE

Remember to enable Link Time Code Generation (LTCG): pass "-ltcg" to "configure.bat" while you are configuring Qt.