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c: Fix compile time hog in c_genericize [PR107127]

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The complex multiplications result in deeply nested set of many SAVE_EXPRs,
which takes even on fast machines over 5 minutes to walk.
This patch fixes that by using walk_tree_without_duplicates where it is
instant.

2022-11-23  Andrew Pinski  <apinski@marvell.com>
	    Jakub Jelinek  <jakub@redhat.com>

	PR c/107127
	* c-gimplify.cc (c_genericize): Use walk_tree_without_duplicates
	instead of walk_tree for c_genericize_control_r.

	* gcc.dg/pr107127.c: New test.
This commit is contained in:
Jakub Jelinek 2022-11-23 19:09:31 +01:00
parent c087fe834b
commit 8a0fce6a51
2 changed files with 14 additions and 2 deletions
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4
gcc/c-family/c-gimplify.cc
View file

@ -572,8 +572,8 @@ c_genericize (tree fndecl)
bc_state_t save_state;
push_cfun (DECL_STRUCT_FUNCTION (fndecl));
save_bc_state (&save_state);
walk_tree (&DECL_SAVED_TREE (fndecl), c_genericize_control_r,
NULL, NULL);
walk_tree_without_duplicates (&DECL_SAVED_TREE (fndecl),
c_genericize_control_r, NULL);
restore_bc_state (&save_state);
pop_cfun ();
}

12
gcc/testsuite/gcc.dg/pr107127.c Normal file
View file

@ -0,0 +1,12 @@
/* PR c/107127 */
/* { dg-do compile } */
/* { dg-options "" } */
int *v;
_Complex double
foo (_Complex double a, double b, double c)
{
return v[0] / ((((c * (0 - 0 / a + 699.0 + 7.05 - 286.0 - +-4.65 + 1.57 + 0) * 0.1 - 3.28 + 4.22 + 0.1)) * b + 5.06)
* 1.23 * 8.0 * 12.0 * 16.0 * 2.0 * 2.0 * 0.25 * 0.125 * 18.2 * -15.25 * 0.0001
* 42.0 * 0.012 - 8.45 + 0 + 88.0 + 6.96 + 867.0 + 9.10 - 7.04 * -1.0);