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))) + 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)); }))))))) +#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; +} + -- 2.25.1
