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| author | Thomas Koenig <tkoenig@gcc.gnu.org> | 2017-10-18 21:29:37 +0000 |
|---|---|---|
| committer | Thomas Koenig <tkoenig@gcc.gnu.org> | 2017-10-18 21:29:37 +0000 |
| commit | e35ba10a77dae0b356d78f36bbabebe053264eb0 (patch) | |
| tree | 7aa37aa9dd5d44e348748e53461b23454160f1f9 /gcc/fortran/frontend-passes.c | |
| parent | 9d0d0a5a1312edb8c32160c5645cf72841efa12d (diff) | |
| download | gcc-e35ba10a77dae0b356d78f36bbabebe053264eb0.zip gcc-e35ba10a77dae0b356d78f36bbabebe053264eb0.tar.gz gcc-e35ba10a77dae0b356d78f36bbabebe053264eb0.tar.bz2 | |
re PR fortran/82567 ([6/7/8] gfortran takes a long time to compile a simple implied-do with -Optimization.)
2017-10-18 Thomas Koenig <tkoenig@gcc.gnu.org>
PR fortran/82567
* frontend-passes.c (combine_array_constructor): If an array
constructor is all constants and has more elements than a small
constant, don't convert a*[b,c] to [a*b,a*c] to reduce compilation
times.
2017-10-18 Thomas Koenig <tkoenig@gcc.gnu.org>
PR fortran/82567
* gfortran.dg/array_constructor_51.f90: New test.
From-SVN: r253872
Diffstat (limited to 'gcc/fortran/frontend-passes.c')
| -rw-r--r-- | gcc/fortran/frontend-passes.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/gcc/fortran/frontend-passes.c b/gcc/fortran/frontend-passes.c index ae4fba6..fcfaf95 100644 --- a/gcc/fortran/frontend-passes.c +++ b/gcc/fortran/frontend-passes.c @@ -1635,6 +1635,8 @@ combine_array_constructor (gfc_expr *e) gfc_constructor *c, *new_c; gfc_constructor_base oldbase, newbase; bool scalar_first; + int n_elem; + bool all_const; /* Array constructors have rank one. */ if (e->rank != 1) @@ -1674,12 +1676,38 @@ combine_array_constructor (gfc_expr *e) if (op2->ts.type == BT_CHARACTER) return false; - scalar = create_var (gfc_copy_expr (op2), "constr"); + /* This might be an expanded constructor with very many constant values. If + we perform the operation here, we might end up with a long compile time + and actually longer execution time, so a length bound is in order here. + If the constructor constains something which is not a constant, it did + not come from an expansion, so leave it alone. */ + +#define CONSTR_LEN_MAX 4 oldbase = op1->value.constructor; + + n_elem = 0; + all_const = true; + for (c = gfc_constructor_first (oldbase); c; c = gfc_constructor_next(c)) + { + if (c->expr->expr_type != EXPR_CONSTANT) + { + all_const = false; + break; + } + n_elem += 1; + } + + if (all_const && n_elem > CONSTR_LEN_MAX) + return false; + +#undef CONSTR_LEN_MAX + newbase = NULL; e->expr_type = EXPR_ARRAY; + scalar = create_var (gfc_copy_expr (op2), "constr"); + for (c = gfc_constructor_first (oldbase); c; c = gfc_constructor_next (c)) { |