| Message ID | 871sihpypa.fsf@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Disable some patterns for fold-left reductions (PR 83965) | expand |
On Mon, Jan 22, 2018 at 6:53 PM, Richard Sandiford <richard.sandiford@linaro.org> wrote: > In this PR we recognised a PLUS_EXPR as a fold-left reduction, > then applied pattern matching to convert it to a WIDEN_SUM_EXPR. > We need to keep the original code in this case since we implement > the reduction using scalar rather than vector operations. > > Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu. > OK to install? Ok. Richard. > Richard > > > 2018-01-22 Richard Sandiford <richard.sandiford@linaro.org> > > gcc/ > PR tree-optimization/83965 > * tree-vect-patterns.c (vect_reassociating_reduction_p): New function. > (vect_recog_dot_prod_pattern, vect_recog_sad_pattern): Use it > instead of checking only for a reduction. > (vect_recog_widen_sum_pattern): Likewise. > > gcc/testsuite/ > PR tree-optimization/83965 > * gcc.dg/vect/pr83965.c: New test. > > Index: gcc/tree-vect-patterns.c > =================================================================== > --- gcc/tree-vect-patterns.c 2018-01-13 18:01:51.240735098 +0000 > +++ gcc/tree-vect-patterns.c 2018-01-22 17:51:06.751462689 +0000 > @@ -217,6 +217,16 @@ vect_recog_temp_ssa_var (tree type, gimp > return make_temp_ssa_name (type, stmt, "patt"); > } > > +/* Return true if STMT_VINFO describes a reduction for which reassociation > + is allowed. */ > + > +static bool > +vect_reassociating_reduction_p (stmt_vec_info stmt_vinfo) > +{ > + return (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def > + && STMT_VINFO_REDUC_TYPE (stmt_vinfo) != FOLD_LEFT_REDUCTION); > +} > + > /* Function vect_recog_dot_prod_pattern > > Try to find the following pattern: > @@ -336,7 +346,7 @@ vect_recog_dot_prod_pattern (vec<gimple > { > gimple *def_stmt; > > - if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def > + if (!vect_reassociating_reduction_p (stmt_vinfo) > && ! STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_vinfo)) > return NULL; > oprnd0 = gimple_assign_rhs1 (last_stmt); > @@ -557,7 +567,7 @@ vect_recog_sad_pattern (vec<gimple *> *s > { > gimple *def_stmt; > > - if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def > + if (!vect_reassociating_reduction_p (stmt_vinfo) > && ! STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_vinfo)) > return NULL; > plus_oprnd0 = gimple_assign_rhs1 (last_stmt); > @@ -1181,7 +1191,7 @@ vect_recog_widen_sum_pattern (vec<gimple > if (gimple_assign_rhs_code (last_stmt) != PLUS_EXPR) > return NULL; > > - if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def > + if (!vect_reassociating_reduction_p (stmt_vinfo) > && ! STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_vinfo)) > return NULL; > > Index: gcc/testsuite/gcc.dg/vect/pr83965.c > =================================================================== > --- /dev/null 2018-01-22 13:31:44.608695204 +0000 > +++ gcc/testsuite/gcc.dg/vect/pr83965.c 2018-01-22 17:51:06.751462689 +0000 > @@ -0,0 +1,18 @@ > +/* { dg-do compile } */ > +/* { dg-additional-options "-ftrapv" } */ > + > +int > +mac (const short *a, const short *b, int sqr, int *sum) > +{ > + int i; > + int dotp = *sum; > + > + for (i = 0; i < 150; i++) > + { > + dotp += b[i] * a[i]; > + sqr += b[i] * b[i]; > + } > + > + *sum = dotp; > + return sqr; > +}
Index: gcc/tree-vect-patterns.c =================================================================== --- gcc/tree-vect-patterns.c 2018-01-13 18:01:51.240735098 +0000 +++ gcc/tree-vect-patterns.c 2018-01-22 17:51:06.751462689 +0000 @@ -217,6 +217,16 @@ vect_recog_temp_ssa_var (tree type, gimp return make_temp_ssa_name (type, stmt, "patt"); } +/* Return true if STMT_VINFO describes a reduction for which reassociation + is allowed. */ + +static bool +vect_reassociating_reduction_p (stmt_vec_info stmt_vinfo) +{ + return (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def + && STMT_VINFO_REDUC_TYPE (stmt_vinfo) != FOLD_LEFT_REDUCTION); +} + /* Function vect_recog_dot_prod_pattern Try to find the following pattern: @@ -336,7 +346,7 @@ vect_recog_dot_prod_pattern (vec<gimple { gimple *def_stmt; - if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def + if (!vect_reassociating_reduction_p (stmt_vinfo) && ! STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_vinfo)) return NULL; oprnd0 = gimple_assign_rhs1 (last_stmt); @@ -557,7 +567,7 @@ vect_recog_sad_pattern (vec<gimple *> *s { gimple *def_stmt; - if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def + if (!vect_reassociating_reduction_p (stmt_vinfo) && ! STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_vinfo)) return NULL; plus_oprnd0 = gimple_assign_rhs1 (last_stmt); @@ -1181,7 +1191,7 @@ vect_recog_widen_sum_pattern (vec<gimple if (gimple_assign_rhs_code (last_stmt) != PLUS_EXPR) return NULL; - if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def + if (!vect_reassociating_reduction_p (stmt_vinfo) && ! STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_vinfo)) return NULL; Index: gcc/testsuite/gcc.dg/vect/pr83965.c =================================================================== --- /dev/null 2018-01-22 13:31:44.608695204 +0000 +++ gcc/testsuite/gcc.dg/vect/pr83965.c 2018-01-22 17:51:06.751462689 +0000 @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-additional-options "-ftrapv" } */ + +int +mac (const short *a, const short *b, int sqr, int *sum) +{ + int i; + int dotp = *sum; + + for (i = 0; i < 150; i++) + { + dotp += b[i] * a[i]; + sqr += b[i] * b[i]; + } + + *sum = dotp; + return sqr; +}