On Fri, 1 Sep 2023, Jiufu Guo wrote: > Hi, > > Integer expression "(X - N * M) / N" can be optimized to "X / N - M" with > the below conditions: > 1. There is no wrap/overflow/underflow. > wrap/overflow/underflow breaks the arithmetic operation. > 2. "X - N * M" and "X" are not of opposite sign. > Here, the operation "/" would be "trunc_div", the fractional part is > discarded towards zero. If "X - N * M" and "X" are in different signs, > then trunc_div discards the fractional parts (of /N) in different > directions. > > Compare the previous version: > https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624801.html > This patch adds comments and update the pattern on "(t + C)" to be more > tight. > > Bootstrap & regtest pass on ppc64{,le} and x86_64. > Is this patch ok for trunk? > > BR, > Jeff (Jiufu Guo) > > PR tree-optimization/108757 > > gcc/ChangeLog: > > * match.pd ((X - N * M) / N): New pattern. > ((X + N * M) / N): New pattern. > ((X + C) div_rshift N): New pattern. > > gcc/testsuite/ChangeLog: > > * gcc.dg/pr108757-1.c: New test. > * gcc.dg/pr108757-2.c: New test. > * gcc.dg/pr108757.h: New test. > > --- > gcc/match.pd | 78 ++++++++++ > gcc/testsuite/gcc.dg/pr108757-1.c | 18 +++ > gcc/testsuite/gcc.dg/pr108757-2.c | 19 +++ > gcc/testsuite/gcc.dg/pr108757.h | 233 ++++++++++++++++++++++++++++++ > 4 files changed, 348 insertions(+) > create mode 100644 gcc/testsuite/gcc.dg/pr108757-1.c > create mode 100644 gcc/testsuite/gcc.dg/pr108757-2.c > create mode 100644 gcc/testsuite/gcc.dg/pr108757.h > > diff --git a/gcc/match.pd b/gcc/match.pd > index > fa598d5ca2e470f9cc3b82469e77d743b12f107e..863bc7299cdefc622a7806a4d32e37268c50d453 > 100644 > --- a/gcc/match.pd > +++ b/gcc/match.pd > @@ -959,6 +959,84 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > #endif > )))) > > +#if GIMPLE > +(for div (trunc_div exact_div) > + /* Simplify (X + M*N) / N -> X / N + M. */ > + (simplify > + (div (plus:c@4 @0 (mult:c@3 @1 @2)) @2) > + (with {value_range vr0, vr1, vr2, vr3, vr4;} > + (if (INTEGRAL_TYPE_P (type) > + && get_range_query (cfun)->range_of_expr (vr1, @1) > + && get_range_query (cfun)->range_of_expr (vr2, @2) > + /* "N*M" doesn't overflow. */ > + && range_op_handler (MULT_EXPR).overflow_free_p (vr1, vr2) > + && get_range_query (cfun)->range_of_expr (vr0, @0) > + && get_range_query (cfun)->range_of_expr (vr3, @3) > + /* "X+(N*M)" doesn't overflow. */ > + && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr3) > + && get_range_query (cfun)->range_of_expr (vr4, @4) > + /* "X+N*M" is not with opposite sign as "X". */ > + && (TYPE_UNSIGNED (type) > + || (vr0.nonnegative_p () && vr4.nonnegative_p ()) > + || (vr0.nonpositive_p () && vr4.nonpositive_p ()))) > + (plus (div @0 @2) @1)))) > + > + /* Simplify (X - M*N) / N -> X / N - M. */ > + (simplify > + (div (minus@4 @0 (mult:c@3 @1 @2)) @2) > + (with {value_range vr0, vr1, vr2, vr3, vr4;} > + (if (INTEGRAL_TYPE_P (type) > + && get_range_query (cfun)->range_of_expr (vr1, @1) > + && get_range_query (cfun)->range_of_expr (vr2, @2) > + /* "N * M" doesn't overflow. */ > + && range_op_handler (MULT_EXPR).overflow_free_p (vr1, vr2) > + && get_range_query (cfun)->range_of_expr (vr0, @0) > + && get_range_query (cfun)->range_of_expr (vr3, @3) > + /* "X - (N*M)" doesn't overflow. */ > + && range_op_handler (MINUS_EXPR).overflow_free_p (vr0, vr3) > + && get_range_query (cfun)->range_of_expr (vr4, @4) > + /* "X-N*M" is not with opposite sign as "X". */ > + && (TYPE_UNSIGNED (type) > + || (vr0.nonnegative_p () && vr4.nonnegative_p ()) > + || (vr0.nonpositive_p () && vr4.nonpositive_p ()))) > + (minus (div @0 @2) @1))))) > + > +/* Simplify > + (X + C) / N -> X / N + C / N where C is multiple of N. > + (X + C) >> N -> X >> N + C>>N if low N bits of C is 0. */ > +(for op (trunc_div exact_div rshift) > + (simplify > + (op (plus@3 @0 INTEGER_CST@1) INTEGER_CST@2) > + (with > + { > + wide_int c = wi::to_wide (@1); > + wide_int n = wi::to_wide (@2); > + bool shift = op == RSHIFT_EXPR; > + #define plus_op1(v) (shift ? wi::rshift (v, n, TYPE_SIGN (type)) \ > + : wi::div_trunc (v, n, TYPE_SIGN (type))) > + #define exact_mod(v) (shift ? wi::ctz (v) >= n.to_shwi () \ > + : wi::multiple_of_p (v, n, TYPE_SIGN (type)))
please indent these full left > + value_range vr0, vr1, vr3; > + } > + (if (INTEGRAL_TYPE_P (type) > + && get_range_query (cfun)->range_of_expr (vr0, @0)) > + (if (exact_mod (c) > + && get_range_query (cfun)->range_of_expr (vr1, @1) > + /* "X+C" doesn't overflow. */ > + && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr1) > + && get_range_query (cfun)->range_of_expr (vr3, @3) > + /* "X+C" and "X" are not of opposite sign. */ > + && (TYPE_UNSIGNED (type) > + || (vr0.nonnegative_p () && vr3.nonnegative_p ()) > + || (vr0.nonpositive_p () && vr3.nonpositive_p ()))) > + (plus (op @0 @2) { wide_int_to_tree (type, plus_op1 (c)); }) > + (if (TYPE_UNSIGNED (type) && c.sign_mask () < 0 > + && exact_mod (-c) > + /* unsigned "X-(-C)" doesn't underflow. */ > + && wi::geu_p (vr0.lower_bound (), -c)) > + (plus (op @0 @2) { wide_int_to_tree (type, -plus_op1 (-c)); }))))))) and #undef them here again. OK with that change. Thanks, Richard. > +#endif > + > (for op (negate abs) > /* Simplify cos(-x) and cos(|x|) -> cos(x). Similarly for cosh. */ > (for coss (COS COSH) > diff --git a/gcc/testsuite/gcc.dg/pr108757-1.c > b/gcc/testsuite/gcc.dg/pr108757-1.c > new file mode 100644 > index > 0000000000000000000000000000000000000000..7908f4bdcb8e225fe311b668efbe8f6db525b4d5 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr108757-1.c > @@ -0,0 +1,18 @@ > +/* PR tree-optimization/108757 */ > +/* { dg-do compile } */ > +/* { dg-options "-O2 -fdump-tree-optimized" } */ > + > +#include <limits.h> > +#define N 5 > +#define M 3 > +#define GAP 0 > +typedef unsigned int UINT; > +typedef int INT; > +#define UMAX UINT_MAX > +#define IMAX INT_MAX > +#define IMIN INT_MIN > +#include "pr108757.h" > + > +/* { dg-final { scan-tree-dump-not " = x_\[0-9\]+\\(D\\) \\+ " "optimized" } > } * > +/* { dg-final { scan-tree-dump-not " = x_\[0-9\]+\\(D\\) \\- " "optimized" } > } */ > +/* { dg-final { scan-tree-dump-not " = b_\[0-9\]+ \\+ " "optimized" } } */ > diff --git a/gcc/testsuite/gcc.dg/pr108757-2.c > b/gcc/testsuite/gcc.dg/pr108757-2.c > new file mode 100644 > index > 0000000000000000000000000000000000000000..82bebd09944f0be2e0690c604723bfe6182acec3 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr108757-2.c > @@ -0,0 +1,19 @@ > +/* PR tree-optimization/108757 */ > +/* { dg-do compile } */ > +/* { dg-options "-O2 -fdump-tree-optimized -fwrapv" } */ > + > +#include <limits.h> > +#define N 4 > +#define M 3 > +#define GAP 2 > +typedef unsigned int UINT; > +typedef int INT; > +#define UMAX UINT_MAX > +#define IMAX INT_MAX > +#define IMIN INT_MIN > +#include "pr108757.h" > + > +/* { dg-final { scan-tree-dump-times " = x_\[0-9\]+\\(D\\) \\+ " 16 > "optimized" } } */ > +/* { dg-final { scan-tree-dump-times " = x_\[0-9\]+\\(D\\) \\- " 3 > "optimized" } } */ > +/* { dg-final { scan-tree-dump-times " \\+ x_\[0-9\]+\\(D\\)" 3 "optimized" > } } */ > + > diff --git a/gcc/testsuite/gcc.dg/pr108757.h b/gcc/testsuite/gcc.dg/pr108757.h > new file mode 100644 > index > 0000000000000000000000000000000000000000..5550199c1ef952f54eaa83087cec25e992057c34 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr108757.h > @@ -0,0 +1,233 @@ > +#define NOINLINE __attribute__ ((noinline)) > +UINT NOINLINE > +opt_u1 (UINT x) > +{ > + if (x < (M * N) - GAP) > + return 0; > + UINT a = x - (M * N); > + UINT b = a / N; > + return b + M; > +} > + > +UINT NOINLINE > +opt_u2 (UINT x) > +{ > + if (x > (UMAX - (M * N) + GAP)) > + return 0; > + UINT a = x + (M * N); > + UINT b = a / N; > + return b - M; > +} > + > +INT NOINLINE > +opt_s1 (INT x) > +{ > + if (x < (M * N) - GAP) > + return 0; > + INT a = x - (M * N); > + INT b = a / N; > + return b + M; > +} > + > +INT NOINLINE > +opt_s2 (INT x) > +{ > + if (x < IMIN + (M * N) - GAP || x > 0) > + return 0; > + INT a = x - (M * N); > + INT b = a / N; > + return b + M; > +} > + > +INT NOINLINE > +opt_s3 (INT x) > +{ > + if (x < (M * N) - GAP) > + return 0; > + INT a = x - (M * N); > + INT b = a / -N; > + return b + -M; > +} > + > +INT NOINLINE > +opt_s4 (INT x) > +{ > + if (x < IMIN + (M * N) - GAP || x > 0) > + return 0; > + INT a = x - (M * N); > + INT b = a / -N; > + return b + -M; > +} > + > +INT NOINLINE > +opt_s5 (INT x) > +{ > + if (x > (-M * N) + GAP) > + return 0; > + INT a = x - (-M * N); > + INT b = a / N; > + return b + -M; > +} > + > +INT NOINLINE > +opt_s6 (INT x) > +{ > + if (x > IMAX - (M * N) + GAP || x < 0) > + return 0; > + INT a = x - (-M * N); > + INT b = a / N; > + return b + -M; > +} > + > +INT NOINLINE > +opt_s7 (INT x) > +{ > + if (x > (M * -N) + GAP) > + return 0; > + INT a = x - (M * -N); > + INT b = a / -N; > + return b + M; > +} > + > +INT NOINLINE > +opt_s8 (INT x) > +{ > + if (x > IMAX - (M * N) + GAP || x < 0) > + return 0; > + INT a = x - (M * -N); > + INT b = a / -N; > + return b + M; > +} > + > +UINT NOINLINE > +opt_u3 (UINT x) > +{ > + if (x < (M << N) - GAP) > + return 0; > + UINT a = x - (M << N); > + UINT b = a >> N; > + return b + M; > +} > + > +UINT NOINLINE > +opt_u4 (UINT x) > +{ > + if (x > (UMAX - (M << N)) + GAP) > + return 0; > + UINT a = x + (M << N); > + UINT b = a >> N; > + return b - M; > +} > + > +INT NOINLINE > +opt_s9 (INT x) > +{ > + if (x < (M << N) - GAP) > + return 0; > + INT a = x - (M << N); > + INT b = a >> N; > + return b + M; > +} > + > +INT NOINLINE > +opt_s10 (INT x) > +{ > + if (x < IMIN + (M << N) - GAP || x > 0) > + return 0; > + INT a = x - (M << N); > + INT b = a >> N; > + return b + M; > +} > + > +INT NOINLINE > +opt_s11 (INT x) > +{ > + if (x > (-M << N) + GAP) > + return 0; > + INT a = x - (-M << N); > + INT b = a >> N; > + return b + -M; > +} > + > +INT NOINLINE > +opt_s12 (INT x) > +{ > + if (x > IMAX - (M << N) + GAP || x < 0) > + return 0; > + INT a = x - (-M << N); > + INT b = a >> N; > + return b + -M; > +} > + > +UINT NOINLINE > +opt_u5 (UINT x, UINT n, UINT m) > +{ > + if (n > N || m > M) > + return 0; > + if (x < (M*N) - GAP) > + return 0; > + UINT a = x - (m * n); > + UINT b = a / n; > + return b + m; > +} > + > +UINT NOINLINE > +opt_u6 (UINT x, UINT n, UINT m) > +{ > + if (n > N || m > M) > + return 0; > + if (x > (UMAX - M*N) + GAP) > + return 0; > + UINT a = x + (m * n); > + UINT b = a / n; > + return b - m; > +} > + > +INT NOINLINE > +opt_s13 (INT x, INT n, INT m) > +{ > + if (n > N || m > M || n < 0 || m < 0) > + return 0; > + if (x < (M*N) - GAP) > + return 0; > + INT a = x - (m * n); > + INT b = a / n; > + return b + m; > +} > + > +INT NOINLINE > +opt_s14 (INT x, INT n, INT m) > +{ > + if (n > N || m > M || n < 0 || m < 0) > + return 0; > + if (x > -M*N + GAP) > + return 0; > + INT a = x + (m * n); > + INT b = a / n; > + return b - m; > +} > + > +INT > +opt_s15 (INT x, INT n, INT m) > +{ > + if (n > 0 || m > 0 || n < -N || m < -M) > + return 0; > + if (x < (M*N) - GAP) > + return 0; > + INT a = x - (m * n); > + INT b = a / n; > + return b + m; > +} > + > +INT NOINLINE > +opt_s16 (INT x, INT n, INT m) > +{ > + if (n > 0 || m > 0 || n < -N || m < -M) > + return 0; > + if (x < 0 || x > (IMAX - M*N) + GAP) > + return 0; > + INT a = x + (m * n); > + INT b = a / n; > + return b - m; > +} > + > -- Richard Biener <rguent...@suse.de> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, Germany; GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)