Intel® 64 and IA-32 Architectures Optimization Reference Manual

APPLICATION PERFORMANCE TOOLSThe /fast option maximizes speed across the entire program. For most Intel 64 andIA-32 processors, the “/fast” option is equivalent to “/O3 /Qipo /QxP” (-Q3 -ipo -static -xP on Linux). For Mac OS, the "-fast" option is equivalent to "-O3 -ipo".All the command-line options are described in Intel ® C++ Compiler documentation.A.1.1Recommended Optimization Settings for Intel 64 and IA-32Processors64-bit addressable code can only run in 64-bit mode of processors that supportIntel 64 architecture. The optimal compiler settings for 64-bit code generation isdifferent from 32-bit code generation. Table A-1 lists recommended compiler optionsfor generating 32-bit code for Intel 64 and IA-32 processors. Table A-1 also appliesto code targeted to run in compatibility mode on an Intel 64 processor, but does notapply to running in 64-bit mode. Table A-2 lists recommended compiler options forgenerating 64-bit code for Intel 64 processors, it only applies to code target to run in64-bit mode. Intel compilers provide separate compiler binary to generate 64-bitcode versus 32-bit code. The 64-bit compiler binary generates only 64-bit addressablecode.Table A-1. Recommended IA-32 Processor Optimization OptionsNeed Recommendation Comments• /QxT (-xT onLinux)Best performanceon Intel Core 2processor family andIntel Xeon processor3000 and 5100series, utilizingSSSE3 and otherprocessor-specificinstructionsBest performanceon Intel Core 2processor family andIntel Xeon processor3000 and 5100series, utilizingSSSE3; runs on non-Intel processorsupporting SSE2Best performanceon IA-32 processorswith SSE3instruction support• /QaxT /QxW (-axT-xW on Linux)• Single code path• Will not run on earlier processors thatdo not support SSSE3• Multiple code path are generated• Be sure to validate your application onall systems where it may be deployed./QxP (-xP on Linux) • Single code path• Will not run on earlier processors.thatdo not support SSE3A-2