From 358ebd8fbfb370b39b331c10e161ff4ea8f7e0e5 Mon Sep 17 00:00:00 2001 From: Harald Anlauf Date: Tue, 22 Jan 2019 21:23:57 +0000 Subject: [PATCH] re PR fortran/88579 (Calculating power of powers of two) 2019-01-22 Harald Anlauf PR fortran/88579 * trans-expr.c (gfc_conv_power_op): Handle cases of (2**e) ** integer and (- 2**e) ** integer. 2019-01-22 Harald Anlauf PR fortran/88579 * gfortran.dg/power_8.f90: New test. From-SVN: r268163 --- gcc/fortran/ChangeLog | 8 ++- gcc/fortran/trans-expr.c | 96 ++++++++++++++++++++++------------- gcc/testsuite/ChangeLog | 5 ++ gcc/testsuite/gfortran.dg/power_8.f90 | 64 +++++++++++++++++++++++ 4 files changed, 136 insertions(+), 37 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/power_8.f90 diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog index a6d793c..31a8b2c 100644 --- a/gcc/fortran/ChangeLog +++ b/gcc/fortran/ChangeLog @@ -1,3 +1,9 @@ +2019-01-22 Harald Anlauf + + PR fortran/88579 + * trans-expr.c (gfc_conv_power_op): Handle cases of (2**e) ** integer + and (- 2**e) ** integer. + 2019-01-19 Dominique d'Humieres PR fortran/37835 @@ -8,7 +14,7 @@ PR fortran/77960 * io.c (match_io_element): input-item cannot be an external function. - + 2018-01-19 Thomas Koenig Paul Thomas diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c index 3238e7c..328ffc9 100644 --- a/gcc/fortran/trans-expr.c +++ b/gcc/fortran/trans-expr.c @@ -3060,19 +3060,44 @@ gfc_conv_power_op (gfc_se * se, gfc_expr * expr) && TREE_CODE (TREE_TYPE (rse.expr)) == INTEGER_TYPE) { wi::tree_to_wide_ref wlhs = wi::to_wide (lse.expr); - HOST_WIDE_INT v; + HOST_WIDE_INT v, w; + int kind, ikind, bit_size; + v = wlhs.to_shwi (); + w = abs (v); + + kind = expr->value.op.op1->ts.kind; + ikind = gfc_validate_kind (BT_INTEGER, kind, false); + bit_size = gfc_integer_kinds[ikind].bit_size; + if (v == 1) { /* 1**something is always 1. */ se->expr = build_int_cst (TREE_TYPE (lse.expr), 1); return; } - else if (v == 2 || v == 4 || v == 8 || v == 16) + else if (v == -1) { - /* 2**n = 1<expr = tmp; + return; + } + else if (w > 0 && ((w & (w-1)) == 0) && ((w >> (bit_size-1)) == 0)) + { + /* Here v is +/- 2**e. The further simplification uses + 2**n = 1<expr = fold_build3_loc (input_location, COND_EXPR, type, cond2, - build_int_cst (type, 0), cond); - return; - } - else if (v == -1) - { - /* (-1)**n is 1 - ((n & 1) << 1) */ - tree type; - tree tmp; - - type = TREE_TYPE (lse.expr); - tmp = fold_build2_loc (input_location, BIT_AND_EXPR, type, - rse.expr, build_int_cst (type, 1)); - tmp = fold_build2_loc (input_location, LSHIFT_EXPR, type, - tmp, build_int_cst (type, 1)); - tmp = fold_build2_loc (input_location, MINUS_EXPR, type, - build_int_cst (type, 1), tmp); - se->expr = tmp; + tmp1 = fold_build3_loc (input_location, COND_EXPR, type, cond2, + build_int_cst (type, 0), cond); + if (v > 0) + { + se->expr = tmp1; + } + else + { + /* for v < 0, calculate v**n = |v|**n * (-1)**n */ + tree tmp2; + tmp2 = fold_build2_loc (input_location, BIT_AND_EXPR, type, + rse.expr, build_int_cst (type, 1)); + tmp2 = fold_build2_loc (input_location, LSHIFT_EXPR, type, + tmp2, build_int_cst (type, 1)); + tmp2 = fold_build2_loc (input_location, MINUS_EXPR, type, + build_int_cst (type, 1), tmp2); + se->expr = fold_build2_loc (input_location, MULT_EXPR, type, + tmp1, tmp2); + } return; } } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index afa010e..66b692e 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2019-01-22 Harald Anlauf + + PR fortran/88579 + * gfortran.dg/power_8.f90: New test. + 2019-01-22 Sandra Loosemore * g++.dg/lto/pr87906_0.C: Add dg-require-effective-target fpic. diff --git a/gcc/testsuite/gfortran.dg/power_8.f90 b/gcc/testsuite/gfortran.dg/power_8.f90 new file mode 100644 index 0000000..143063b --- /dev/null +++ b/gcc/testsuite/gfortran.dg/power_8.f90 @@ -0,0 +1,64 @@ +! { dg-do run } +! { dg-additional-options "-fdump-tree-original" } +! +! PR88579 - Test optimizations for bases that are powers of 2 or -2. +program p + implicit none + integer(4) :: i, u + integer(1) :: j, v + integer(2) :: k, w + integer(8) :: z + ! Test selected positive bases + u = 1 + do i=1,5 + u = u * 64_4 + if (u /= 64_4 ** i) stop 1 + end do + z = 1 + do i=1,7 + z = z * 256_8 + if (z /= 256_8 ** i) stop 2 + end do + z = 1 + do i=1,3 + z = z * 65536_8 + if (z /= 65536_8 ** i) stop 3 + end do + ! Test selected negative bases and integer kind combinations + u = 1 + do i=1,7 + u = u * (-2_1) + if (u /= (-2_1) ** i) stop 4 + end do + v = 1 + do j=1,7 + v = v * (-2_1) + if (v /= (-2_1) ** j) stop 5 + end do + v = 1 + do k=1,7 + v = v * (-2_1) + if (v /= (-2_1) ** k) stop 6 + end do + w = 1 + do k=1,7 + w = w * (-4_2) + if (w /= (-4_2) ** k) stop 7 + end do + w = 1 + do i=1,5 + w = w * (-8_2) + if (w /= (-8_2) ** i) stop 8 + end do + u = 1 + do i=1,1 + u = u * (-HUGE(1_4)/2-1) + if (u /= (-HUGE(1_4)/2-1) ** i) stop 9 + end do + z = 1 + do i=1,7 + z = z * (-512_8) + if (z /= (-512_8) ** i) stop 10 + end do +end program p +! { dg-final { scan-tree-dump-not "_gfortran_pow" "original" } } -- 2.7.4