Base Compiler Invocation
C benchmarks
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- opencc
![[user]](http://www.spec.org/auto/cpu2006/flags/user.png)
- CC, LD
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Invoke the Open64 C compiler.
Also used to invoke linker for C programs.
C++ benchmarks
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- openCC
- CXX, LD
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Invoke the Open64 C++ compiler.
Also used to invoke linker for C++ programs.
Invoke the Open64 C compiler.
Also used to invoke linker for C programs.
Invoke the Open64 C++ compiler.
Also used to invoke linker for C++ programs.
![[benchmark]](http://www.spec.org/auto/cpu2006/flags/benchmark.png)
This macro specifies that the target system uses the LP64 data model; specifically, that integers are 32 bits, while longs and pointers are 64 bits.
This macro indicates that the benchmark is being compiled on an AMD64-compatible system running the Linux operating system.
![[suite]](http://www.spec.org/auto/cpu2006/flags/suite.png)
This option is used to indicate that the host system's integers are 32-bits wide, and longs and pointers are 64-bits wide. Not all benchmarks recognize this macro, but the preferred practice for data model selection applies the flags to all benchmarks; this flag description is a placeholder for those benchmarks that do not recognize this macro.
This option is used to indicate that the host system's integers are 32-bits wide, and longs and pointers are 64-bits wide. Not all benchmarks recognize this macro, but the preferred practice for data model selection applies the flags to all benchmarks; this flag description is a placeholder for those benchmarks that do not recognize this macro.
This option is used to indicate that the host system's integers are 32-bits wide, and longs and pointers are 64-bits wide. Not all benchmarks recognize this macro, but the preferred practice for data model selection applies the flags to all benchmarks; this flag description is a placeholder for those benchmarks that do not recognize this macro.
This option is used to indicate that the host system's integers are 32-bits wide, and longs and pointers are 64-bits wide. Not all benchmarks recognize this macro, but the preferred practice for data model selection applies the flags to all benchmarks; this flag description is a placeholder for those benchmarks that do not recognize this macro.
This option is used to indicate that the host system's integers are 32-bits wide, and longs and pointers are 64-bits wide. Not all benchmarks recognize this macro, but the preferred practice for data model selection applies the flags to all benchmarks; this flag description is a placeholder for those benchmarks that do not recognize this macro.
This option is used to indicate that the host system's integers are 32-bits wide, and longs and pointers are 64-bits wide. Not all benchmarks recognize this macro, but the preferred practice for data model selection applies the flags to all benchmarks; this flag description is a placeholder for those benchmarks that do not recognize this macro.
This option is used to indicate that the host system's integers are 32-bits wide, and longs and pointers are 64-bits wide. Not all benchmarks recognize this macro, but the preferred practice for data model selection applies the flags to all benchmarks; this flag description is a placeholder for those benchmarks that do not recognize this macro.
Portability changes for Linux
This option is used to indicate that the host system's integers are 32-bits wide, and longs and pointers are 64-bits wide. Not all benchmarks recognize this macro, but the preferred practice for data model selection applies the flags to all benchmarks; this flag description is a placeholder for those benchmarks that do not recognize this macro.
This flag can be set for SPEC compilation for Linux using default compiler.
Compiler will generate instructions and schedule them appropriately for the selected processor type. The default value, auto, means to optimize for the platform on which the compiler is running, as determined by reading /proc/cpuinfo. anyx86 means a generic 32-bit x86 processor without SSE2 support.
Instructs the compiler to perform aggressive optimizations that are likely to improve the scalability of an application running on a system with multi-core processors. In particular, these optimizations may target machine resources that are shared among the multiple cores of a processor, e.g. memory bandwidth, shared L3 cache, etc.
Uses a selection of optimizations in order to maximize performance.
Specifying "-Ofast" is equivalent to -O3 -ipa -OPT:Ofast -fno-math-errno -ffast-math.
These optimization options are generally safe. Floating-point accuracy may
be affected due to the transformation of the computational code. Note the
interprocedural analysis option, -ipa, specifies limitations on how libraries
and object files (.o files) are built.
-CG:local_sched_alg=(0|1|2): This option selects the basic block instruction scheduling algorithm.
To perform backward scheduling (i.e. where instructions are
scheduled from the bottom to the top of the basic block) select 0.
To perform forward scheduling select 1.
To schedule the instruction twice (i.e. once in the forward
direction and once in the backward direction) and take the
optimal of the two schedules select 2.
The default value for this option is determined by the Open64 compiler
during compilation.
-INLINE:aggressive=(on|off|0|1): Instructs the compiler to be very aggressive when performing inlining. The default is "-INLINE:aggressive=OFF".
-IPA:plimit=N: The compiler is instructed to halt inlining within a program once the intermediate representation indicates that the code size of the program has surpassed the limit set by N. The default is "-IPA:plimit=2500".
-IPA:small_pu=N: The compiler is instructed not to restrict a procedure from inlining with a code size smaller than N when invoking the "-IPA:plimit" flag. The default is "-IPA:small_pu=30".
Compiler will generate instructions and schedule them appropriately for the selected processor type. The default value, auto, means to optimize for the platform on which the compiler is running, as determined by reading /proc/cpuinfo. anyx86 means a generic 32-bit x86 processor without SSE2 support.
Instructs the compiler to perform aggressive optimizations that are likely to improve the scalability of an application running on a system with multi-core processors. In particular, these optimizations may target machine resources that are shared among the multiple cores of a processor, e.g. memory bandwidth, shared L3 cache, etc.
Uses a selection of optimizations in order to maximize performance.
Specifying "-Ofast" is equivalent to -O3 -ipa -OPT:Ofast -fno-math-errno -ffast-math.
These optimization options are generally safe. Floating-point accuracy may
be affected due to the transformation of the computational code. Note the
interprocedural analysis option, -ipa, specifies limitations on how libraries
and object files (.o files) are built.
Generate code for a 32-bit environment. The 32-bit environment sets int, long and pointer to 32 bits and generates code that runs on any i386 system. The compiler generates x86 or IA32 32-bit ABI. The default on a 32-bit host is 32-bit ABI. The default on a 64-bit host is 64-bit ABI if the target platform specified is 64-bit, otherwise the default is 32-bit.
-INLINE:aggressive=(on|off|0|1): Instructs the compiler to be very aggressive when performing inlining. The default is "-INLINE:aggressive=OFF".
-CG:cmp_peep=(on|off|0|1): Instructs the compiler to perform aggressive load execution peeps on compare operations. Note for 32-bit environments the default is "-CG:cmp_peep=ON". The default is "CG:cmp_peep=OFF".
The Hoard Memory Allocator V3.7.1 available from http://www.hoard.org
This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.
Perform all the optimizations at the -O2 level as well as many more aggressive optimizations. Examples of such aggressive optimizations are loop nest optimizations and generation of prefetch instructions. Although these more aggressive optimizations can significantly speed up the run time execution of the compiled program, in rare cases they may not be profitable and may instead lead to a slow down. Also, some of these more aggressive optimizations may affect the accuracy of some floating point computations.
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective. Level 2 is assumed if no value is specified (i.e. "-O". The default is "-O2".
Perform extensive global optimizations. Examples of such optimizations are control flow optimizations, partial redundancy elimination, and strength reduction. These optimizations can very often reduce the execution time of the compiled program significantly, but they may do so at the expense of increased compilation time. This is the default level of optimization.
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective. Level 2 is assumed if no value is specified (i.e. "-O". The default is "-O2".
Perform minimal local optimizations on sections of straight-line code (basic blocks) only. Examples of such optimizations are instruction scheduling and some peephole optimizations. These optimizations do not usually have any noticeable impact on compilation time.
If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective. Level 2 is assumed if no value is specified (i.e. "-O". The default is "-O2".
Instructs the compiler to invoke inter-procedural analysis. Specifying "-ipa" is equivalent to "-IPA" and "-IPA:" with no suboptions, thus the default settings for the individual IPA suboptions are used.
-OPT:Ofast
Maximizes performance for a given platform using the selected optimizations.
"-OPT:Ofast" specifies four optimizations; "-OPT:ro=2",
"-OPT:Olimit=0", "-OPT:div_split=ON", and "-OPT:alias=typed".
Note the specified optimizations are ordinarily safe but floating
point accuracy due to transformations may be diminished.
-OPT:roundoff,ro=(0|1|2|3)
"-OPT:roundoff" specifies acceptable levels of divergence for both
accuracy and overflow/underflow behavior of floating-point results
relative to the source language rules. The roundoff value is
in the range 0-3 with each value described as follows:
0 Do no transformations which could affect floating-point
results. The default for optimization levels "-O0", "-O1",
and "-O2".
1 Allow all transformations which have a limited affect
on floating-point results. For roundoff, limited is defined
as only the last bit or two of the mantissa is affected.
For overflow or underflow, limited is defined as
intermediate results of the transformed calculation may
overflow or underflow within a factor of two of where
the original expression may have overflowed or underflowed.
Note that effects may be less limited when
compounded by multiple transformations. This is the
default when "-O3" is specified.
2 Specifies transformations with extensive effects on
floating-point results. For example, allow associative
rearrangement (i.e. even across loop iterations) and the
distribution of multiplication over addition or
subtraction. Do not specify transformations known to
cause: a. cumulative roundoff errors, or b. overflow/underflow
of operands in a large range of valid floating-point values.
This is the default when specifying "-OPT:Ofast".
3 Specify any mathematically valid transformation of
floating-point expressions. For example, floating point
induction variables in loops are permitted (even if
known to cause cumulative roundoff errors). Also
permitted are fast algorithms for complex absolute
value and divide (which will overflow/underflow for
operands beyond the square root of the representable extremes).
-OPT:Olimit=N
Controls the size of procedures to be optimized. Procedures above
the specified cutoff limit, N, are not optimized. N=0 means
"infinite Olimit", which causes all procedures to be optimized
with no consideration regarding compilation times. Note if
"-OPT:Ofast" is enabled then "-OPT:Olimit=0" or when "-O3" is
enabled "-OPT:Olimit=9000". The default is "-OPT:Olimit=6000".
-OPT:div_split=(on|off|0|1)
Instruct the compiler to transform x/y into x*(recip(y)). Flags
-OPT:Ofast or -OPT:IEEE_arithmetic=3 will enable this optimization.
Note this transform generates fairly accurate code. The default
is "-OPT:div_split=OFF".
The "-OPT:" option group controls various optimizations. The "-OPT:" options supersede the defaults that are based on the main optimization level.
-OPT:alias=<model>
Identify which pointer aliasing model to use. The compiler will
make assumptions during compilation when one or more of the
following <model> is specified:
typed
Assumes that two pointers of different types will not
point to the same location in memory (i.e. the code
adheres to the ANSI/ISO C standards). Note when
specifying "-OPT:Ofast" turns this option ON.
(restricted|restrict)
Assumes that distinct pointers are pointing to distinct
non-overlapping objects. The default is that this optimization
is disabled.
disjoint
Assumes that any two pointer expressions are pointing
to distinct non-overlapping objects. This default is that this
optimization is disabled.
no_f90_pointer_alias
Assumes that any two different Fortran 90 pointers are
pointing to distinct non-overlapping objects. The default
is that this optimization is disabled.
Do not set ERRNO after calling math functions that are executed with a single instruction, e.g. sqrt. A program that relies on IEEE exceptions for math error handling may want to use this flag for speed while maintaining IEEE arithmetic compatibility. Note specifying "-Ofast" implies "-fno-math-errno". The default is "-fmath-errno".
"-fast-math" instructs the compiler to relax ANSI/ISO or IEEE
rules/specifications for math functions in order to optimize
floating-point computations to improve runtime.
"-fno-fast-math" instructs the compiler to conform to ANSI and
IEEE math rules. This option causes the preprocessor macro
__FAST_MATH__ to be defined.
Note:
"-Ofast" implies "-ffast-math".
"-ffast-math" sets options "-fno-math-errno" and "-OPT:IEEE_arithmetic=2".
"-fno-fast-math" sets options "-fmath-errno" and "-OPT:IEEE arithmetic=1".
Flag description origin markings:
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Indicates that the flag description came from the user flags file. |
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Indicates that the flag description came from the suite-wide flags file. |
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Indicates that the flag description came from a per-benchmark flags file. |
For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact webmaster@spec.org
Copyright 2006-2014 Standard Performance Evaluation Corporation
Tested with SPEC CPU2006 v1.1.
Report generated on Thu Jul 24 01:07:04 2014 by SPEC CPU2006 flags formatter v6906.