Flags file for AMD Submissions using SPEC CPU v1.3 and Pathscale 2.3 Compiler
Copyright 2003, 2004, 2005 PathScale, Inc. All Rights Reserved.
PathScale EKOPath(TM) Compiler Suite (Fortran, C and C++ compilers)
flag descriptions, for SPEC CPU2000 submissions.
Portability Flags:
-DSPEC_CPU2000_LP64 Compile using LP64 programming model.
-DLINUX_i386 Linux Intel system, use "long long" as
64bit variable.
-DHAS_ERRLIST Prog env provides specification for
"sys_errlist[]".
-DSPEC_CPU2000_NEED_BOOL Use SPEC provided definition of the boolean type.
-DSPEC_CPU2000_LINUX_I386 Compile for an I386 system running Linux.
-DPSEC_CPU2000_GLIBC22 Compatibility with 2.2 & later versions of glibc
-DSYS_IS_USG Specifies that the operating system is
USG compliant.
-DSYS_HAS_TIME_PROTO Do not explicitly declare time().
-DSYS_HAS_IOCTL_PROTO Do not explicitly declare ioctl().
-DSYS_HAS_CALLOC_PROTO Do not explicitly declare calloc().
-fixedform tells f90 compiler to use fixed format
(F77 72 column format), instead of F90 free format.
Optimization Flags:
Some suboptions either enable or disable the feature. To enable a feature,
either specify only the suboption name or specify =1, =ON, or =TRUE. Disabling
a feature, is accomplished by adding =0, =OFF, or =FALSE. These values are
insensitive to case: 'on' & 'ON' mean the same thing. Below, ON & OFF indicate
the enabling or disabling of a feature.
-CG[:...]
Code Generation option group: control the optimizations
and transformations of the instruction-level code generator.
-CG:cflow=(ON|OFF)
A value of OFF disables control flow optimization in the code
generation. Default is ON.
-CG:gcm=(ON|OFF)
Specifying OFF disables the instruction-level global code
motion optimization phase. The default is ON.
-CG:load_exe=n
Specifies the threshold for subsuming a memory load operation into
the operand of an arithmetic instruction. The value of 0 turns
off this subsumption optimization. The default is 1, when this
subsumption is performed only when the result of the load has only
one use. This subsumption is not performed if the number of times
the result of the load is used exceeds the value n, a non-negative
integer.
-CG:local_fwd_sched=(ON|OFF)
Changes the instruction scheduling algorithm to work forward
instead of backward for the instructions in each basic block.
The default is OFF.
-CG:movnti=N
Convert ordinary stores to non-temporal stores when writing memory
blocks of size larger than N KB. When N is set to 0, this
transformation is avoided. The default value is 120 (KB).
-CG:p2align=(ON|OFF)
Align loop heads to 64-byte boundaries. The default is
OFF.
-CG:p2align_freq=n
Aligns branch targets based on execution frequency. This option
is meaningful only under feedback-directed compilation. The
default value n=0 turns off the alignment optimization. Any
other value specifies the frequency threshold at or above which
this alignment will be performed by the compiler.
-CG:prefetch=(ON|OFF)
Turning this OFF suppresses any generation of prefetch instructions
in the code generator. This has the same effect as -LNO:prefetch=0.
The default is ON which implies using default prefetch algorithms.
-CG:prefetchnta=(ON|OFF)
Prefetch when data is non-temporal at all levels of the cache
hierarchy. This is for data streaming situations in which the
data will not need to be re-used soon. The default is OFF.
-fb_create <prefix for feedback data files>
Used to specify that an instrumented executable program
is to be generated. Such an executable is suitable for
producing feedback data files with the specified prefix
for use in feedback-directed compilation (FDO). The commonly
used prefix is "fbdata". This is OFF by default.
-fb_opt <prefix for feedback data files>
Used to specify feedback-directed compilation (FDO) by extracting
feedback data from files with the specified prefix, which were
previously generated using -fb_create. The commonly used prefix
is "fbdata". This optimization is off by default.
-fno-exceptions
Tells the compiler that the program does not use exception
handling, so it can perform more aggressive optimization in
the code. The generation of exception handling constructs
is also suppressed. Under this flag, code that uses exception
handling cannot be guaranteed to work correctly. Note that
the absence of exception handling construct does not mean
that the function can be compiled with this flag. For
exception handling to work preperly, the scopes
crossed between throwing and catching an exception must
all have been compiled with exceptions on.
-fno-math-errno
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.
This is implied by -Ofast. The default is -fmath-errno.
-GRA:optimize_boundary=(ON|OFF)
Allow the Global Register Allocator to allocate the same
register to different variables in the same basic-block.
Default is OFF.
-INLINE:aggressive=(ON|OFF)
Tells the compiler to be more aggressive about inlining. The
default is -INLINE:aggressive=OFF.
-IPA[:...]
IPA option group: control the inter-procedural analyses and
transformations performed. Note that giving just the group name
without any options, i.e., -IPA, will invoke the interprocedural
analyzer. -IPA is off by default unless -Ofast is specified.
-ipa Same as -IPA alone.
-IPA:callee_limit=(n)
Functions whose size exceeds this limit will never be
automatically inlined by the compiler. The default is n=2000.
-IPA:ctype=(ON|OFF)
Turns on optimizations that speed up interfaces to the constructs
defined in ctype.h by assuming that the program will not be run
in a multi-threaded environment. The default is OFF.
-IPA:field_reorder=(ON|OFF)
Enables the re-ordering of fields in large structs based
on their reference patterns in feedback compilation to
minimize data cache misses. The default is OFF.
-IPA:linear=(ON|OFF)
Controls conversion of a multi-dimensional array to a single
dimensional (linear) array that covers the same block of memory.
When inlining Fortran subroutines, IPA tries to map formal
array parameters to the shape of the actual parameter. In the
case that it cannot map the parameter, it linearizes the array
reference. By default, IPA will not inline such callsites
because they may cause performance problems. The default is OFF.
-IPA:min_hotness=N
When feedback information is available, a call site to a
procedure must be invoked with a count that exceeds the
threshold specified by N before the procedure will be inlined
at that call site. The default is 10.
-IPA:plimit=(n)
Inline calls to a procedure until the procedure has grown to
size of n. The default is 2500.
-IPA:pu_reorder=(0|1|2)
Controls the phase that optimizes the layout of the program
units (functions) in the program.
0 = Disables procedure reordering (default)
1 = Reorder based on the frequency in which different
procedures are invoked.
2 = Reorder based on caller-callee relationship.
-IPA:small_pu=(n)
A procedure with size smaller than n is not subjected to the
plimit restriction.The default is n=30
-IPA:space=N
Inline until a program expansion of N% is reached. For example,
-IPA:space=20 limits code expansion due to inlining to approx-
imately 20%. Default is no limit.
-IPA:use_intrinsic[=(ON|OFF)]
Enable/disable loading the intrinsic version of standard library
functions. The default is OFF.
-L/opt/acml2.7.0/pathscale64/lib -lacml
The flags above are needed to use the PathScale compiler to link
with the ACML (AMD Core Math Library) 2.7.0 library. The
PathScale-compiled, 64-bit version of ACML that gets installed
at /opt/acml2.7.0/gnu64 by default. ACML is available as a free
download from http://developer.amd.com/acml.aspx.
-LNO:
option group specifies options and transformations performed
on loop nests. The -LNO: option group is enabled only if the -O3
option is also specified on the compiler command line.
-LNO:blocking[=(ON|OFF)]
Enable/disable the cache blocking transformation. The default
is on at -O3 or higher.
-LNO:fission=(0|1|2)
This option controls loop fission. The options can be one of the
following:
0 = Disables loop fission (default)
1 = Performs normal fission as necessary
2 = Specifies that fission be tried before fusion
If -LNO:fission=1:fusion=1 or -LNO:fission=2:fusion=2 are spec-
ified, then fusion is performed.
-LNO:full_unroll,fu=N
Fully unroll innermost loops with trip_count <= N inside LNO.
N can be any integer between 0 and 100. The default value for N
is 5. Setting this flag to 0 disables full unrolling of small
trip count loops inside LNO.
-LNO:full_unroll_size=N
Fully unroll innermost loops with unrolled loop size <= N inside
LNO. N can be any integer between 0 and 10000. The conditions
implied by the full_unroll option must also be satisfied for
the loop to be fully unrolled. The default value for N is 1600.
-LNO:full_unroll_outer=(ON|OFF)
Control the full unrolling of loops with known trip count that
do not contain a loop and are not contained in a loop. The
conditions implied by both the full_unroll and the
full_unroll_size options must be satisfied for the loop to be
fully unrolled. The default is OFF.
-LNO:fusion=n
Perform loop fusion, n: 0 - off, 1 - conservative, 2 - aggressive.
The default is 1.
-LNO:prefetch[=(0|1|2|3)]
Specify level of prefetching.
0 = Prefetch disabled.
1 = Prefetch is done only for arrays that are always
referenced in each iteration of a loop, the default.
2 = Prefetch is done without the above restrictions.
3 = Most aggressive.
-LNO:prefetch_ahead=n
Prefetch n cache line(s) ahead. The default is 2.
-LNO:simd=(0|1|2)
This option enables or disables inner loop vectorization.
0 = Turn off the vectorizer.
1 = (Default) Vectorize only if the compiler can determine that
there is no undesirable performance impact due to sub-optimal
alignment. Vectorize only if vectorization does not introduce
accuracy problems with floating-point operations.
2 = Vectorize without any constraints (most aggressive).
-m32
Generates code according to the 32-bit ABI, also known as x86
or IA32.
-m64
Compile for 64-bit ABI, also known as AMD64, x86_64, or IA32e.
This is the default.
-m3dnow Enable use of 3DNow instructions. The default is OFF.
-mcpu=(opteron|athlon64|athlon64fx|em64t|pentium4|xeon|anyx86|auto)
Compiler will optimize code for selected platform. auto means to
optimize for the platform that the compiler is running on, which
the compiler determines by reading /proc/cpuinfo. anyx86 means a
generic 32-bit x86 processor without SSE2 support. The
default is opteron.
-msse2
Enable use of SSE2 instructions. This is the default under
both -m64 and -m32.
-mno-sse2
This flag is only applicable to -m32. -mno-sse2 is ignored
under -m64 with a warning.
-O or -O2
Turn on extensive optimization. The optimizations at this level are
generally conservative, in the sense that they (1) are virtually
always beneficial, (2) provide improvements commensurate to the
compile time spent to achieve them, and (3) avoid changes which
affect such things as floating point accuracy.
-O3
Turn on aggressive optimization. The optimizations at this level
are distinguished from -O2 by their aggressiveness, generally
seeking highest-quality generated code even if it requires extensive
compile time. They may include optimizations which are generally
beneficial but occasionally hurt performance. This includes but
is not limited to turning on the Loop Nest Optimizer, -LNO:opt=1,
and setting -OPT:ro=1:IEEE_arith=2:Olimit=9000.
-Ofast Equivalent to "-O3 -ipa -OPT:Ofast -fno-math-errno." -OPT:Ofast is
described below.
-OPT:alias=<name>
Specifies the pointer aliasing model to be used. By
specifiying one or more of the following for <name>, the
compiler is able to make assumptions throughout the compilation:
typed Assume that the code adheres to the ANSI/ISO C
standard which states that two pointers of different
types cannot point to the same location in memory.
This is on by default when -Ofast is specified.
restrict Specifies that distinct pointers are assumed
to point to distinct, non-overlapping objects.
This is off by default.
disjoint Specifies that any two pointer expressions are
assumed to point to distinct, non-overlapping objects.
This is off by default.
-OPT:div_split=(ON|OFF)
Enable/disable changing x/y into x*(recip(y)). This is
OFF by default but is enabled by -OPT:Ofast or
-OPT:IEEE_arithmetic=3.
-OPT:early_intrinsics=(ON|OFF)
When ON, this option causes calls to intrinsics to be
expanded to inline code early in the backend compilation.
This may enable more vectorization opportunities if vector
forms of the expanded operations exist. Default is OFF.
-OPT:fast_complex=(ON|OFF)
Setting fast_complex=ON enables fast calculations for values
declared to be of type complex. When this is set to ON,
complex absolute value (norm) and complex division use fast
algorithms that are more likely to overflow or underflow than
the standard algorithms. OFF is the default. fast_complex=ON
is enabled if -OPT:roundoff=3 is in effect.
-OPT:fast_nint=(ON|OFF)
This option uses a hardware feature to implement NINT and ANINT
(both single- and double-precision versions). Default is OFF but
fast_nint=ON is enabled by default if -OPT:ro=3 is in effect.
-OPT:goto=(OFF|ON)
Disable/enable the conversion of GOTOs into higher level
structures like FOR loops. The default is ON for -O2 or higher.
-OPT:IEEE_arithmetic,IEEE_arith,IEEE_a=(n)
specify level of conformance to IEEE 754 floating pointing
roundoff/overflow behavior. n can be one of the following:
1 Adheres to IEEE accuracy. This is the default when
optimization levels -O0, -O1 and -O2 are in effect.
2. May produce inexact result not conforming to IEEE 754.
This is the default when -O3 is in effect.
3. All mathematically valid transformations are allowed.
-OPT:IEEE_NaN_Inf=(ON|OFF)
OFF specifies non-IEEE-754 results in operations that might
have IEEE 754 NaN or infinity operands; this enables many
optimizations which would be invalid for NaN or infinity
operands. The default is ON.
-OPT:transform_to_memlib=(ON|OFF)
When ON, this option enables transformation of loop constructs
to calls to memcpy or memset. Default is ON when target
processor is EM64T, OFF otherwise.
-OPT:Ofast
Use optimizations selected to maximize performance.
Although the optimizations are generally safe,
they may affect floating point accuracy due to rearrangement
of computations. This effectively turns on the following
optimizations: -OPT:ro=2:Olimit=0:div_split=ON:alias=typed.
-OPT:Olimit=(n)
Disable optimization when size of program unit is > n. When n
is 0, program unit size is ignored and optimization process
will not be disabled due to compile time limit. The default is
0 when -Ofast is specified, otherwise the default is 6000
under -O2 and 9000 under -O3.
-OPT:roundoff,ro=(n)
Specifies the level of acceptable departure from source
language floating-point, round-off, and overflow semantics. n
can be one of the following:
0 Inhibits optimizations that might affect the
floating-point behavior. This is the default when
optimization levels -O0, -O1, and -O2 are in effect.
1 Allows simple transformations that might cause limited
round-off or overflow differences. Compounding such
transformations could have more extensive effects.
This is the default level when -O3 is in effect.
2 Allows more extensive transformations, such as the
reordering of reduction loops. This is the default
level when -Ofast is specified.
3 Enables any mathematically valid transformation.
-OPT:treeheight=(ON|OFF)
The value ON turns on re-association in expressions to reduce
the expressions' tree height. The default value is OFF.
-OPT:unroll_analysis=(ON|OFF)
The default value of ON lets the compiler analyze the
content of the loop to determine the best unrolling
parameters, instead of strictly adhering to the
-OPT:unroll_times_max and -OPT:unroll_size parameters.
-OPT:unroll_times_max,unroll_times=(n)
Unroll inner loops by a maximum of n. The default is 4.
-OPT:unroll_size=(n)
Sets the ceiling of maximum number of instructions for an
unrolled inner loop. If n = 0, the ceiling is disregarded.
-static
Suppresses dynamic linking at run-time for shared libraries;
uses static linking instead.
-TENV:X=(0|1|2|3|4)
Specify the level of enabled exceptions that will be assumed
for purposes of performing speculative code motion (default
is 1 at all optimization levels). In general, an instruction
will not be speculated (i.e. moved above a branch by the
optimizer) unless any exceptions it might cause are disabled
by this option. At level 0, no speculative code motion may
be performed. At level 1, safe speculative code motion may
be performed, with IEEE-754 underflow and inexact exceptions
disabled. At level 2, all IEEE-754 exceptions are disabled
except divide by zero. At level 3, all IEEE-754 exceptions
are disabled including divide by zero. At level 4, memory
exceptions may be disabled or ignored.
-TENV:frame_pointer=(ON|OFF)
Default is ON for C++ and OFF otherwise.
Local variables in the function stack frame are addressed via
the frame pointer register. Ordinarily, the compiler will
replace this use of frame pointer by addressing local variables
via the stack pointer when it determines that the stack pointer
is fixed throughout the function invocation. This frees up the
frame pointer for other purposes. Turning this flag on forces
the compiler to use the frame pointer to address local variables.
This flag defaults to on for C++ because the exception handling
mechanism relies on the frame pointer register being used to
address local variables. This flag can be turned off for C++
for programs that do not throw exceptions.
-Wl,-x
Passes the -x option to the linker. With this flag set, the
linker will not preserve local (non-global) symbols in the output
symbol table. The linker enters external and static symbols
only. This option conserves space in the output file. This is
OFF by default.
-WOPT:aggstr=N
This controls the aggressiveness of the strength reduction optimiz-
ation performed by the scalar optimizer, in which induction
expressions within a loop are replaced by temporaries that are
incremented together with the loop variable. When strength
reduction is overdone, the additional temporaries increase
register pressure, resulting in excessive register spills that
decrease performance. The value specified must be a positive
integer value, which specifies the maximum number of induction
expressions that will be strength-reduced across an index variable
increment. When set at 0, strength reduction is only per-
formed for non-trivial induction expressions. The default is 11.
-WOPT:if_conv=(0|1|2)
Controls the optimization that translates simple IF statements
to conditional move instructions in the target CPU. Setting to
0 suppresses this optimization. The value of 1 designates
conservative if-conversion, in which the context around the IF
statement is used in deciding whether to if-convert. The value
of 2 enables aggressive if-conversion by causing it to be per-
formed regardless of the context. The default is 1.
-WOPT:mem_opnds=(ON|OFF)
ON makes the scalar optimizer preserve any memory operands of
arithmetic operations so as to help bring about subsumption of
memory loads into the operands of arithmetic operations. Load
subsumption is the combining of an arithmetic instruction and
a memory load into one instruction. The default is OFF.
-WOPT:retype_expr=(ON|OFF)
ON enables the optimization in the compiler that converts 64-bit
address computation to use 32-bit arithmetic as much as
possible. The default is OFF.
-WOPT:unroll=(0|1|2)
Control the unrolling of innermost loops in the scalar optimizer.
Setting to 0 suppresses this unroller. The default is 1, which
makes the scalar optimizer unroll only loops that contain IF
statements. Setting to 2 makes the unrolling to also apply to
loop bodies that are straight line code, which duplicates the
unrolling done in the code generator, and is thus unnecessary.
The default setting of 1 makes this unrolling complementary to
what is done in the code generator. This unrolling is not
affected by the unrolling options under the -OPT group.
-WOPT:val=(0|1|2)
Controls the number of times the value-numbering optimization is
performed in the global optimizer, with the default being 1.
This optimization tries to recognize expressions that will
compute identical run-time values and changes the program to avoid
re-computing them.