| Message ID | 20171218215050.GJ2353@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | Improve vect_create_epilog_for_reduction (PR tree-optimization/80631) | expand |
On 12/18/2017 02:50 PM, Jakub Jelinek wrote: > Hi! > > When backporting the wrong-code bugfix parts of PR80631 to 7.3, I've noticed > that we perform the optimization to use the induc_val only when reduc_fn is > IFN_REDUC_{MAX,MIN}. That is true e.g. for AVX2, but not plain SSE2, so if > we have a loop like: > void foo (int *v) > { > int found_index = -17; > for (int k = 0; k < 64; k++) > if (v[k] == 77) > found_index = k; > return found_index; > } > we start with { -17, -17, -17... } only for avx* and can optimize away > the scalar if (reduc_result == -17 ? -17 : reduc_result, but for sse* > we start instead with { -1, -1, -1... } and can't optimize > if (reduc_result == -1 ? -17 : reduc_result. > > Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for > trunk? > > 2017-12-18 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/80631 > * tree-vect-loop.c (vect_create_epilog_for_reduction): Compare > induc_code against MAX_EXPR or MIN_EXPR instead of reduc_fn against > IFN_REDUC_MAX or IFN_REDUC_MIN. OK. jeff
On Mon, 18 Dec 2017, Jakub Jelinek wrote: > Hi! > > When backporting the wrong-code bugfix parts of PR80631 to 7.3, I've noticed > that we perform the optimization to use the induc_val only when reduc_fn is > IFN_REDUC_{MAX,MIN}. That is true e.g. for AVX2, but not plain SSE2, so if > we have a loop like: > void foo (int *v) > { > int found_index = -17; > for (int k = 0; k < 64; k++) > if (v[k] == 77) > found_index = k; > return found_index; > } > we start with { -17, -17, -17... } only for avx* and can optimize away > the scalar if (reduc_result == -17 ? -17 : reduc_result, but for sse* > we start instead with { -1, -1, -1... } and can't optimize > if (reduc_result == -1 ? -17 : reduc_result. > > Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for > trunk? Ok. > 2017-12-18 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/80631 > * tree-vect-loop.c (vect_create_epilog_for_reduction): Compare > induc_code against MAX_EXPR or MIN_EXPR instead of reduc_fn against > IFN_REDUC_MAX or IFN_REDUC_MIN. > > --- gcc/tree-vect-loop.c.jj 2017-12-12 09:54:28.000000000 +0100 > +++ gcc/tree-vect-loop.c 2017-12-15 18:56:15.426591727 +0100 > @@ -4432,9 +4432,9 @@ vect_create_epilog_for_reduction (vec<tr > && (STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) > == INTEGER_INDUC_COND_REDUCTION) > && !integer_zerop (induc_val) > - && ((reduc_fn == IFN_REDUC_MAX > + && ((induc_code == MAX_EXPR > && tree_int_cst_lt (initial_def, induc_val)) > - || (reduc_fn == IFN_REDUC_MIN > + || (induc_code == MIN_EXPR > && tree_int_cst_lt (induc_val, initial_def)))) > induc_val = initial_def; > vect_is_simple_use (initial_def, loop_vinfo, &def_stmt, &initial_def_dt); > > Jakub > >
--- gcc/tree-vect-loop.c.jj 2017-12-12 09:54:28.000000000 +0100 +++ gcc/tree-vect-loop.c 2017-12-15 18:56:15.426591727 +0100 @@ -4432,9 +4432,9 @@ vect_create_epilog_for_reduction (vec<tr && (STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) == INTEGER_INDUC_COND_REDUCTION) && !integer_zerop (induc_val) - && ((reduc_fn == IFN_REDUC_MAX + && ((induc_code == MAX_EXPR && tree_int_cst_lt (initial_def, induc_val)) - || (reduc_fn == IFN_REDUC_MIN + || (induc_code == MIN_EXPR && tree_int_cst_lt (induc_val, initial_def)))) induc_val = initial_def; vect_is_simple_use (initial_def, loop_vinfo, &def_stmt, &initial_def_dt);
Hi! When backporting the wrong-code bugfix parts of PR80631 to 7.3, I've noticed that we perform the optimization to use the induc_val only when reduc_fn is IFN_REDUC_{MAX,MIN}. That is true e.g. for AVX2, but not plain SSE2, so if we have a loop like: void foo (int *v) { int found_index = -17; for (int k = 0; k < 64; k++) if (v[k] == 77) found_index = k; return found_index; } we start with { -17, -17, -17... } only for avx* and can optimize away the scalar if (reduc_result == -17 ? -17 : reduc_result, but for sse* we start instead with { -1, -1, -1... } and can't optimize if (reduc_result == -1 ? -17 : reduc_result. Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2017-12-18 Jakub Jelinek <jakub@redhat.com> PR tree-optimization/80631 * tree-vect-loop.c (vect_create_epilog_for_reduction): Compare induc_code against MAX_EXPR or MIN_EXPR instead of reduc_fn against IFN_REDUC_MAX or IFN_REDUC_MIN. Jakub