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* [gcc r10-11241] Fortran: fix corner case of IBITS intrinsic [PR108937]
@ 2023-03-05 19:36 Harald Anlauf
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From: Harald Anlauf @ 2023-03-05 19:36 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:570828e84f751730743093e5f060eeaf98c08cac
commit r10-11241-g570828e84f751730743093e5f060eeaf98c08cac
Author: Harald Anlauf <anlauf@gmx.de>
Date: Mon Feb 27 21:37:11 2023 +0100
Fortran: fix corner case of IBITS intrinsic [PR108937]
gcc/fortran/ChangeLog:
PR fortran/108937
* trans-intrinsic.c (gfc_conv_intrinsic_ibits): Handle corner case
LEN argument of IBITS equal to BITSIZE(I).
gcc/testsuite/ChangeLog:
PR fortran/108937
* gfortran.dg/ibits_2.f90: New test.
(cherry picked from commit 6cce953ebec274f1468d5d3a0697cf05bb43b8f6)
Diff:
---
gcc/fortran/trans-intrinsic.c | 10 ++++++++++
gcc/testsuite/gfortran.dg/ibits_2.f90 | 32 ++++++++++++++++++++++++++++++++
2 files changed, 42 insertions(+)
diff --git a/gcc/fortran/trans-intrinsic.c b/gcc/fortran/trans-intrinsic.c
index 9a4aa08f889..1d3ad31eb59 100644
--- a/gcc/fortran/trans-intrinsic.c
+++ b/gcc/fortran/trans-intrinsic.c
@@ -6502,6 +6502,7 @@ gfc_conv_intrinsic_ibits (gfc_se * se, gfc_expr * expr)
tree type;
tree tmp;
tree mask;
+ tree num_bits, cond;
gfc_conv_intrinsic_function_args (se, expr, args, 3);
type = TREE_TYPE (args[0]);
@@ -6542,8 +6543,17 @@ gfc_conv_intrinsic_ibits (gfc_se * se, gfc_expr * expr)
"in intrinsic IBITS", tmp1, tmp2, nbits);
}
+ /* The Fortran standard allows (shift width) LEN <= BIT_SIZE(I), whereas
+ gcc requires a shift width < BIT_SIZE(I), so we have to catch this
+ special case. See also gfc_conv_intrinsic_ishft (). */
+ num_bits = build_int_cst (TREE_TYPE (args[2]), TYPE_PRECISION (type));
+
mask = build_int_cst (type, -1);
mask = fold_build2_loc (input_location, LSHIFT_EXPR, type, mask, args[2]);
+ cond = fold_build2_loc (input_location, GE_EXPR, logical_type_node, args[2],
+ num_bits);
+ mask = fold_build3_loc (input_location, COND_EXPR, type, cond,
+ build_int_cst (type, 0), mask);
mask = fold_build1_loc (input_location, BIT_NOT_EXPR, type, mask);
tmp = fold_build2_loc (input_location, RSHIFT_EXPR, type, args[0], args[1]);
diff --git a/gcc/testsuite/gfortran.dg/ibits_2.f90 b/gcc/testsuite/gfortran.dg/ibits_2.f90
new file mode 100644
index 00000000000..2af5542d764
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/ibits_2.f90
@@ -0,0 +1,32 @@
+! { dg-do run }
+! { dg-additional-options "-fcheck=bits" }
+! PR fortran/108937 - Intrinsic IBITS(I,POS,LEN) fails when LEN equals
+! to BIT_SIZE(I)
+! Contributed by saitofuyuki@jamstec.go.jp
+
+program test_bits
+ implicit none
+ integer, parameter :: KT = kind (1)
+ integer, parameter :: lbits = bit_size (0_KT)
+ integer(kind=KT) :: x, y0, y1
+ integer(kind=KT) :: p, l
+
+ x = -1
+ p = 0
+ do l = 0, lbits
+ y0 = ibits (x, p, l)
+ y1 = ibits_1(x, p, l)
+ if (y0 /= y1) then
+ print *, l, y0, y1
+ stop 1+l
+ end if
+ end do
+contains
+ elemental integer(kind=KT) function ibits_1(I, POS, LEN) result(n)
+ !! IBITS(I, POS, LEN) = (I >> POS) & ~((~0) << LEN)
+ implicit none
+ integer(kind=KT),intent(in) :: I
+ integer, intent(in) :: POS, LEN
+ n = IAND (ISHFT(I, - POS), NOT(ISHFT(-1_KT, LEN)))
+ end function ibits_1
+end program test_bits
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