Hi, Integer expression "(X - N * M) / N" can be optimized to "X / N - M" if there is no wrap/overflow/underflow and "X - N * M" has the same sign with "X".
Compare with the previous version: https://gcc.gnu.org/pipermail/gcc-patches/2023-June/620896.html This version changes: 1. Remove the behavior to convert 'm' to '-m' for unsigned variable. This kind of case is rare, and it makes the code ambiguous. 2. Use the 'capture' expression and avoid building new expressions. 3. Add APIs like get_range and nonpositive/nonnegative. 4. Refactor patterns in match.pd and function names and signatures. While some APIs are still in gimple-fold.cc/h. Tried to add them to other files, but did not find a better place. Thanks for comments/suggestions! 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: * gimple-fold.cc (mult_without_overflow_p): New function. (plus_without_overflow_p): New function. (minus_without_overflow_p): New function. (same_sign_p): New function. * gimple-fold.h (mult_without_overflow_p): New declare. (plus_without_overflow_p): New declare. (minus_without_overflow_p): New declare. (same_sign_p): New declare. * match.pd ((X - N * M) / N): New pattern. ((X + N * M) / N): New pattern. ((X + C) div_rshift N): New pattern. * value-query.h (get_range): New function. * value-range.cc (irange::nonnegative_p): New function. (irange::nonpositive_p): New function. * value-range.h (irange::nonnegative_p): New declare. (irange::nonpositive_p): New declare. gcc/testsuite/ChangeLog: * gcc.dg/pr108757-1.c: New test. * gcc.dg/pr108757-2.c: New test. * gcc.dg/pr108757.h: New test. --- gcc/gimple-fold.cc | 132 +++++++++++++++++ gcc/gimple-fold.h | 4 + gcc/match.pd | 54 +++++++ gcc/value-query.h | 10 ++ gcc/value-range.cc | 12 ++ gcc/value-range.h | 2 + gcc/testsuite/gcc.dg/pr108757-1.c | 18 +++ gcc/testsuite/gcc.dg/pr108757-2.c | 19 +++ gcc/testsuite/gcc.dg/pr108757.h | 233 ++++++++++++++++++++++++++++++ 9 files changed, 484 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/gimple-fold.cc b/gcc/gimple-fold.cc index 581575b65ec..c0703b45c4b 100644 --- a/gcc/gimple-fold.cc +++ b/gcc/gimple-fold.cc @@ -9349,3 +9349,135 @@ gimple_stmt_integer_valued_real_p (gimple *stmt, int depth) return false; } } + +/* Return true if "X * Y" may be overflow on integer TYPE. */ + +bool +mult_without_overflow_p (tree x, tree y, tree type) +{ + gcc_assert (INTEGRAL_TYPE_P (type)); + + if (TYPE_OVERFLOW_UNDEFINED (type)) + return true; + + value_range vr0; + value_range vr1; + if (!(get_range (vr0, x) && get_range (vr1, y))) + return false; + + wi::overflow_type ovf; + signop sgn = TYPE_SIGN (type); + wide_int wmax0 = vr0.upper_bound (); + wide_int wmax1 = vr1.upper_bound (); + wi::mul (wmax0, wmax1, sgn, &ovf); + if (ovf != wi::OVF_NONE) + return false; + + if (TYPE_UNSIGNED (type)) + return true; + + wide_int wmin0 = vr0.lower_bound (); + wide_int wmin1 = vr1.lower_bound (); + wi::mul (wmin0, wmin1, sgn, &ovf); + if (ovf != wi::OVF_NONE) + return false; + + wi::mul (wmin0, wmax1, sgn, &ovf); + if (ovf != wi::OVF_NONE) + return false; + + wi::mul (wmax0, wmin1, sgn, &ovf); + if (ovf != wi::OVF_NONE) + return false; + + return true; +} + +/* Return true if "X + Y" may be overflow on integer TYPE. */ + +bool +plus_without_overflow_p (tree x, tree y, tree type) +{ + gcc_assert (INTEGRAL_TYPE_P (type)); + + if (TYPE_OVERFLOW_UNDEFINED (type)) + return true; + + value_range vr0; + value_range vr1; + if (!(get_range (vr0, x) && get_range (vr1, y))) + return false; + + wi::overflow_type ovf; + signop sgn = TYPE_SIGN (type); + wide_int wmax0 = vr0.upper_bound (); + wide_int wmax1 = vr1.upper_bound (); + wi::add (wmax0, wmax1, sgn, &ovf); + if (ovf != wi::OVF_NONE) + return false; + + if (TYPE_UNSIGNED (type)) + return true; + + wide_int wmin0 = vr0.lower_bound (); + wide_int wmin1 = vr1.lower_bound (); + wi::add (wmin0, wmin1, sgn, &ovf); + if (ovf != wi::OVF_NONE) + return false; + + return true; +} + +/* Return true if "X - Y" may be overflow on integer TYPE. */ + +bool +minus_without_overflow_p (tree x, tree y, tree type) +{ + gcc_assert (INTEGRAL_TYPE_P (type)); + + if (TYPE_OVERFLOW_UNDEFINED (type)) + return true; + + value_range vr0; + value_range vr1; + if (!(get_range (vr0, x) && get_range (vr1, y))) + return false; + + wi::overflow_type ovf; + signop sgn = TYPE_SIGN (type); + wide_int wmin0 = vr0.lower_bound (); + wide_int wmax1 = vr1.upper_bound (); + wi::sub (wmin0, wmax1, sgn, &ovf); + if (ovf != wi::OVF_NONE) + return false; + + if (TYPE_UNSIGNED (type)) + return true; + + wide_int wmax0 = vr0.upper_bound (); + wide_int wmin1 = vr1.lower_bound (); + wi::sub (wmax0, wmin1, sgn, &ovf); + if (ovf != wi::OVF_NONE) + return false; + + return true; +} + +/* Return true if "X" and "Y" have the same sign or zero. */ + +bool +same_sign_p (tree x, tree y, tree type) +{ + gcc_assert (INTEGRAL_TYPE_P (type)); + + if (TYPE_UNSIGNED (type)) + return true; + + value_range vr0; + value_range vr1; + if (!(get_range (vr0, x) && get_range (vr1, y))) + return false; + + return (vr0.nonnegative_p () && vr1.nonnegative_p ()) + || (vr0.nonpositive_p () && vr1.nonpositive_p ()); +} diff --git a/gcc/gimple-fold.h b/gcc/gimple-fold.h index 2fd58db9a2e..76c3fe15559 100644 --- a/gcc/gimple-fold.h +++ b/gcc/gimple-fold.h @@ -64,6 +64,10 @@ extern gimple_seq rewrite_to_defined_overflow (gimple *, bool = false); extern void replace_call_with_value (gimple_stmt_iterator *, tree); extern tree tree_vec_extract (gimple_stmt_iterator *, tree, tree, tree, tree); extern void gsi_replace_with_seq_vops (gimple_stmt_iterator *, gimple_seq); +extern bool mult_without_overflow_p (tree, tree, tree); +extern bool plus_without_overflow_p (tree, tree, tree); +extern bool minus_without_overflow_p (tree, tree, tree); +extern bool same_sign_p (tree, tree, tree); /* gimple_build, functionally matching fold_buildN, outputs stmts int the provided sequence, matching and simplifying them on-the-fly. diff --git a/gcc/match.pd b/gcc/match.pd index 16482b741ea..ca1defd6692 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -942,6 +942,60 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) #endif )))) +#if GIMPLE +(for div (trunc_div exact_div) + /* Simplify (t + M*N) / N -> t / N + M. */ + (simplify + (div (plus:c@4 @0 (mult:c@3 @1 @2)) @2) + (if (INTEGRAL_TYPE_P (type) + && mult_without_overflow_p (@1, @2, type) + && plus_without_overflow_p (@0, @3, type) + && same_sign_p (@0, @4, type)) + (plus (div @0 @2) @1))) + + /* Simplify (t - M*N) / N -> t / N - M. */ + (simplify + (div (minus@4 @0 (mult:c@3 @1 @2)) @2) + (if (INTEGRAL_TYPE_P (type) + && mult_without_overflow_p (@1, @2, type) + && minus_without_overflow_p (@0, @3, type) + && same_sign_p (@0, @4, type)) + (minus (div @0 @2) @1)))) + +/* Simplify + (t + C) / N -> t / N + C / N where C is multiple of N. + (t + C) >> N -> t >> 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 neg_c = TYPE_UNSIGNED (type) && c.sign_mask () < 0; + c = neg_c ? -c : c; + bool ok = INTEGRAL_TYPE_P (type); + if (ok) + ok = code == RSHIFT_EXPR ? wi::ctz (c) >= n.to_shwi () + : wi::multiple_of_p (c, n, TYPE_SIGN (type)); + if (ok) + ok = neg_c + ? minus_without_overflow_p (@0, wide_int_to_tree (type, c), type) + : plus_without_overflow_p (@0, @1, type); + if (ok) + ok = same_sign_p (@0, @3, type); + } + (if (ok) + (with + { + wide_int m; + m = op == RSHIFT_EXPR ? wi::rshift (c, n, TYPE_SIGN (type)) + : wi::div_trunc (c, n, TYPE_SIGN (type)); + m = neg_c ? -m : m; + } + (plus (op @0 @2) { wide_int_to_tree(type, m); })))))) +#endif + (for op (negate abs) /* Simplify cos(-x) and cos(|x|) -> cos(x). Similarly for cosh. */ (for coss (COS COSH) diff --git a/gcc/value-query.h b/gcc/value-query.h index d10c3eac1e2..2c4b9819d5a 100644 --- a/gcc/value-query.h +++ b/gcc/value-query.h @@ -137,6 +137,16 @@ get_range_query (const struct function *fun) return (fun && fun->x_range_query) ? fun->x_range_query : &global_ranges; } +/* Return true if there is range for "X" expression at "S" statement, + and the range is not varying and not undefined. */ + +inline bool +get_range (vrange &r, tree x, gimple *s = NULL) +{ + return get_range_query (cfun)->range_of_expr (r, x, s) && !r.varying_p () + && !r.undefined_p (); +} + // Query the global range of NAME in function F. Default to cfun. extern void gimple_range_global (vrange &v, tree name, struct function *f = cfun); diff --git a/gcc/value-range.cc b/gcc/value-range.cc index 707b1f15fd4..7ab9f56aec3 100644 --- a/gcc/value-range.cc +++ b/gcc/value-range.cc @@ -287,6 +287,18 @@ add_vrange (const vrange &v, inchash::hash &hstate, } //namespace inchash +bool +irange::nonnegative_p () const +{ + return wi::ge_p (lower_bound (), 0, TYPE_SIGN (type ())); +} + +bool +irange::nonpositive_p () const +{ + return wi::le_p (upper_bound (), 0, TYPE_SIGN (type ())); +} + bool irange::supports_type_p (const_tree type) const { diff --git a/gcc/value-range.h b/gcc/value-range.h index 2b4ebabe7c8..4dad4666a32 100644 --- a/gcc/value-range.h +++ b/gcc/value-range.h @@ -145,6 +145,8 @@ public: virtual bool singleton_p (tree *result = NULL) const override; bool singleton_p (wide_int &) const; bool contains_p (const wide_int &) const; + bool nonnegative_p () const; + bool nonpositive_p () const; // In-place operators. virtual bool union_ (const vrange &) override; diff --git a/gcc/testsuite/gcc.dg/pr108757-1.c b/gcc/testsuite/gcc.dg/pr108757-1.c new file mode 100644 index 00000000000..7908f4bdcb8 --- /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 00000000000..82bebd09944 --- /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 00000000000..5550199c1ef --- /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; +} + -- 2.39.3