1LLC(1)                               LLVM                               LLC(1)
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NAME

6       llc - LLVM static compiler
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SYNOPSIS

9       llc [options] [filename]
10

DESCRIPTION

12       The  llc command compiles LLVM source inputs into assembly language for
13       a specified architecture.  The assembly language  output  can  then  be
14       passed  through a native assembler and linker to generate a native exe‐
15       cutable.
16
17       The choice of architecture for the output assembly  code  is  automati‐
18       cally  determined from the input file, unless the -march option is used
19       to override the default.
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OPTIONS

22       If filename is "-" or omitted, llc reads from standard  input.   Other‐
23       wise, it will from filename.  Inputs can be in either the LLVM assembly
24       language format (.ll) or the LLVM bitcode format (.bc).
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26       If the -o option is omitted, then llc will send its output to  standard
27       output if the input is from standard input.  If the -o option specifies
28       "-", then the output will also be sent to standard output.
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30       If no -o option is specified and an input file other than "-" is speci‐
31       fied,  then  llc  creates the output filename by taking the input file‐
32       name, removing any existing .bc extension, and adding a .s suffix.
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34       Other llc options are described below.
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36   End-user Options
37       -help  Print a summary of command line options.
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39       -o <filename>
40              Use <filename> as the output filename. See the summary above for
41              more details.
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43       -O=uint
44              Generate  code  at  different optimization levels.  These corre‐
45              spond to the -O0, -O1, -O2, and -O3 optimization levels used  by
46              clang.
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48       -mtriple=<target triple>
49              Override  the target triple specified in the input file with the
50              specified string.
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52       -march=<arch>
53              Specify the architecture for which to generate  assembly,  over‐
54              riding  the target encoded in the input file.  See the output of
55              llc -help for a list of valid architectures.  By default this is
56              inferred  from  the target triple or autodetected to the current
57              architecture.
58
59       -mcpu=<cpuname>
60              Specify a specific chip in the current architecture to  generate
61              code  for.   By  default this is inferred from the target triple
62              and autodetected to the current architecture.   For  a  list  of
63              available CPUs, use:
64
65                 llvm-as < /dev/null | llc -march=xyz -mcpu=help
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67       -filetype=<output file type>
68              Specify  what kind of output llc should generated.  Options are:
69              asm for textual assembly ( '.s'), obj for  native  object  files
70              ('.o') and null for not emitting anything (for performance test‐
71              ing).
72
73              Note that not all targets support all options.
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75       -mattr=a1,+a2,-a3,...
76              Override or control specific attributes of the target,  such  as
77              whether  SIMD operations are enabled or not.  The default set of
78              attributes is set by the current CPU.  For a list  of  available
79              attributes, use:
80
81                 llvm-as < /dev/null | llc -march=xyz -mattr=help
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83       --frame-pointer
84              Specify   effect   of  frame  pointer  elimination  optimization
85              (all,non-leaf,none).
86
87       --disable-excess-fp-precision
88              Disable optimizations that  may  produce  excess  precision  for
89              floating  point.   Note  that  this option can dramatically slow
90              down code on some systems (e.g. X86).
91
92       --enable-no-infs-fp-math
93              Enable optimizations that assume no Inf values.
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95       --enable-no-nans-fp-math
96              Enable optimizations that assume no NAN values.
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98       --enable-no-signed-zeros-fp-math
99              Enable FP math optimizations  that  assume  the  sign  of  0  is
100              insignificant.
101
102       --enable-no-trapping-fp-math
103              Enable  setting  the  FP  exceptions  build attribute not to use
104              exceptions.
105
106       --enable-unsafe-fp-math
107              Enable optimizations that make  unsafe  assumptions  about  IEEE
108              math (e.g. that addition is associative) or may not work for all
109              input ranges.  These optimizations allow the code  generator  to
110              make  use  of  some  instructions  which  would otherwise not be
111              usable (such as fsin on X86).
112
113       --stats
114              Print statistics recorded by code-generation passes.
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116       --time-passes
117              Record the amount of time needed  for  each  pass  and  print  a
118              report to standard error.
119
120       --load=<dso_path>
121              Dynamically  load  dso_path  (a  path  to  a  dynamically shared
122              object) that implements an LLVM target.  This  will  permit  the
123              target  name  to be used with the -march option so that code can
124              be generated for that target.
125
126       -meabi=[default|gnu|4|5]
127              Specify which EABI version should conform to.  Valid  EABI  ver‐
128              sions  are gnu, 4 and 5.  Default value (default) depends on the
129              triple.
130
131       -stack-size-section
132              Emit the .stack_sizes section which contains  stack  size  meta‐
133              data.  The section contains an array of pairs of function symbol
134              values (pointer size) and stack  sizes  (unsigned  LEB128).  The
135              stack  size values only include the space allocated in the func‐
136              tion prologue. Functions with dynamic stack allocations are  not
137              included.
138
139       -remarks-section
140              Emit the __remarks (MachO) section which contains metadata about
141              remark diagnostics.
142
143   Tuning/Configuration Options
144       --print-machineinstrs
145              Print generated machine code between compilation phases  (useful
146              for debugging).
147
148       --regalloc=<allocator>
149              Specify  the  register allocator to use.  Valid register alloca‐
150              tors are:
151
152              basic
153                 Basic register allocator.
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155              fast
156                 Fast register allocator. It is the  default  for  unoptimized
157                 code.
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159              greedy
160                 Greedy  register  allocator.  It is the default for optimized
161                 code.
162
163              pbqp
164                 Register allocator based on  'Partitioned  Boolean  Quadratic
165                 Programming'.
166
167       --spiller=<spiller>
168              Specify  the spiller to use for register allocators that support
169              it.  Currently this option is used only by the linear scan  reg‐
170              ister  allocator.  The default spiller is local.  Valid spillers
171              are:
172
173              simple
174                 Simple spiller
175
176              local
177                 Local spiller
178
179   Intel IA-32-specific Options
180       --x86-asm-syntax=[att|intel]
181              Specify whether to  emit  assembly  code  in  AT&T  syntax  (the
182              default) or Intel syntax.
183

EXIT STATUS

185       If  llc  succeeds, it will exit with 0.  Otherwise, if an error occurs,
186       it will exit with a non-zero value.
187

SEE ALSO

189       lli(1)
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AUTHOR

192       Maintained by the LLVM Team (https://llvm.org/).
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195       2003-2020, LLVM Project
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20011                                2020-10-15                            LLC(1)
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