GIMPLE

You can see the full documentation about what GIMPLE is here. In this document we will explain how to generate it.

First, we'll copy the content from gcc/gcc/testsuite/jit.dg/test-const-attribute.c into a file named local.c and remove the content we're not interested into:

- /* { dg-do compile { target x86_64-*-* } } */
...
- /* We don't want set_options() in harness.h to set -O3 to see that the const
-    attribute affects the optimizations. */
- #define TEST_ESCHEWS_SET_OPTIONS
- static void set_options (gcc_jit_context *ctxt, const char *argv0)
- {
-   // Set "-O3".
-   gcc_jit_context_set_int_option(ctxt, GCC_JIT_INT_OPTION_OPTIMIZATION_LEVEL, 3);
- }
-
- #define TEST_COMPILING_TO_FILE
- #define OUTPUT_KIND      GCC_JIT_OUTPUT_KIND_ASSEMBLER
- #define OUTPUT_FILENAME  "output-of-test-const-attribute.c.s"
- #include "harness.h"
...
- /* { dg-final { jit-verify-output-file-was-created "" } } */
- /* Check that the loop was optimized away */
- /* { dg-final { jit-verify-assembler-output-not "jne" } } */

Then we'll add a main function which will call the create_code function but also add the calls we need to generate the GIMPLE:

int main() {
    gcc_jit_context *ctxt = gcc_jit_context_acquire();
    create_code(ctxt, NULL);
    gcc_jit_context_dump_to_file(ctxt, "tmp.gimple", 1);
    return 0;
}

Then we can compile it by using:

gcc local.c -I `pwd`/gcc/gcc/jit/ -L `pwd`/gcc-build/gcc -lgccjit -o out

And finally when you run it:

LD_LIBRARY_PATH=`pwd`/gcc-build/gcc LIBRARY_PATH=`pwd`/gcc-build/gcc ./out

You should now have a file named tmp.gimple which contains:

__attribute__((const))
int xxx ()
{
  int D.3394;
  int sum;
  int x;

  <D.3377>:
  x = 45;
  sum = 0;
  goto loop_cond;
  loop_cond:
  x = x >> 1;
  if (x != 0) goto after_loop; else goto loop_body;
  loop_body:
  _1 = foo (x);
  _2 = _1 * 2;
  x = x + _2;
  goto loop_cond;
  after_loop:
  D.3394 = sum;
  return D.3394;
}

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GIMPLE

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