LLC(1) LLVM Command Guide LLC(1)NAMEllc - LLVM static compiler
SYNOPSISllc [options] [filename]
DESCRIPTION
The llc command compiles LLVM source inputs into assembly language for
a specified architecture. The assembly language output can then be
passed through a native assembler and linker to generate a native
executable.
The choice of architecture for the output assembly code is
automatically determined from the input file, unless the -march option
is used to override the default.
OPTIONS
If filename is - or omitted, llc reads from standard input. Otherwise,
it will from filename. Inputs can be in either the LLVM assembly
language format (.ll) or the LLVM bitcode format (.bc).
If the -o option is omitted, then llc will send its output to standard
output if the input is from standard input. If the -o option specifies
-, then the output will also be sent to standard output.
If no -o option is specified and an input file other than - is
specified, then llc creates the output filename by taking the input
filename, removing any existing .bc extension, and adding a .s suffix.
Other llc options are as follows:
End-user Options
-help
Print a summary of command line options.
-O=uint
Generate code at different optimization levels. These correspond to
the -O0, -O1, -O2, -O3, and -O4 optimization levels used by llvm-
gcc and clang.
-mtriple=target triple
Override the target triple specified in the input file with the
specified string.
-march=arch
Specify the architecture for which to generate assembly, overriding
the target encoded in the input file. See the output of llc-help
for a list of valid architectures. By default this is inferred
from the target triple or autodetected to the current architecture.
-mcpu=cpuname
Specify a specific chip in the current architecture to generate
code for. By default this is inferred from the target triple and
autodetected to the current architecture. For a list of available
CPUs, use: llvm-as < /dev/null | llc -march=xyz -mcpu=help
-mattr=a1,+a2,-a3,...
Override or control specific attributes of the target, such as
whether SIMD operations are enabled or not. The default set of
attributes is set by the current CPU. For a list of available
attributes, use: llvm-as < /dev/null | llc -march=xyz -mattr=help
--disable-fp-elim
Disable frame pointer elimination optimization.
--disable-excess-fp-precision
Disable optimizations that may produce excess precision for
floating point. Note that this option can dramatically slow down
code on some systems (e.g. X86).
--enable-no-infs-fp-math
Enable optimizations that assume no Inf values.
--enable-no-nans-fp-math
Enable optimizations that assume no NAN values.
--enable-unsafe-fp-math
Enable optimizations that make unsafe assumptions about IEEE math
(e.g. that addition is associative) or may not work for all input
ranges. These optimizations allow the code generator to make use
of some instructions which would otherwise not be usable (such as
fsin on X86).
--enable-correct-eh-support
Instruct the lowerinvoke pass to insert code for correct exception
handling support. This is expensive and is by default omitted for
efficiency.
--stats
Print statistics recorded by code-generation passes.
--time-passes
Record the amount of time needed for each pass and print a report
to standard error.
--load=dso_path
Dynamically load dso_path (a path to a dynamically shared object)
that implements an LLVM target. This will permit the target name to
be used with the -march option so that code can be generated for
that target.
Tuning/Configuration Options
--print-machineinstrs
Print generated machine code between compilation phases (useful for
debugging).
--regalloc=allocator
Specify the register allocator to use. The default allocator is
local. Valid register allocators are:
simple
Very simple "always spill" register allocator
local
Local register allocator
linearscan
Linear scan global register allocator
iterativescan
Iterative scan global register allocator
--spiller=spiller
Specify the spiller to use for register allocators that support it.
Currently this option is used only by the linear scan register
allocator. The default spiller is local. Valid spillers are:
simple
Simple spiller
local
Local spiller
Intel IA-32-specific Options
--x86-asm-syntax=att|intel
Specify whether to emit assembly code in AT&T syntax (the default)
or intel syntax.
EXIT STATUS
If llc succeeds, it will exit with 0. Otherwise, if an error occurs,
it will exit with a non-zero value.
SEE ALSO
lli
AUTHORS
Maintained by the LLVM Team (<http://llvm.org/>).
CVS 2011-12-13 LLC(1)
