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| author | Thomas Koenig <tkoenig@gcc.gnu.org> | 2025-02-16 12:15:40 +0100 |
|---|---|---|
| committer | Thomas Koenig <tkoenig@gcc.gnu.org> | 2025-02-17 08:19:29 +0100 |
| commit | b57e6e1b38cdaf7a982474d93ebede1cc30f1d46 (patch) | |
| tree | 5f277fd5cf87f250d3fe81ebe571b03d133e1f74 /gcc/fortran/trans-expr.cc | |
| parent | 46276080e726421f6683db08e2bb42fd8d3367a6 (diff) | |
| download | gcc-b57e6e1b38cdaf7a982474d93ebede1cc30f1d46.zip gcc-b57e6e1b38cdaf7a982474d93ebede1cc30f1d46.tar.gz gcc-b57e6e1b38cdaf7a982474d93ebede1cc30f1d46.tar.bz2 | |
Avoid shift wider than unsigned HOST_WIDE_INT on unsigned integer exponentiation.
this patch is a variation of Jakub's patch in the PR, which
avoids overflow on the mask used for exponentiation and
fixes unsigned HOST_WIDE_INT. I tried testing this on
a POWER machine, but --with-build-config=bootstrap-ubsan
fails bootstrap there.
gcc/fortran/ChangeLog:
PR fortran/118862
* trans-expr.cc (gfc_conv_cst_int_power): Use functions for
unsigned wide integer.
(gfc_conv_cst_uint_power): Avoid generating the mask if it would
overflow an unsigned HOST_WIDE_INT. Format fixes.
Diffstat (limited to 'gcc/fortran/trans-expr.cc')
| -rw-r--r-- | gcc/fortran/trans-expr.cc | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc index 9d29fe7..8a3e737 100644 --- a/gcc/fortran/trans-expr.cc +++ b/gcc/fortran/trans-expr.cc @@ -3603,7 +3603,7 @@ gfc_conv_cst_int_power (gfc_se * se, tree lhs, tree rhs) if (bit_size(rhs) < bit_size(lhs)) ! Checked here. return lhs ** rhs; - mask = (1 < bit_size(a) - 1) / 2; + mask = 1 << (bit_size(a) - 1) / 2; return lhs ** (n & rhs); } if (rhs > bit_size(lhs)) ! Checked here. @@ -3623,13 +3623,13 @@ gfc_conv_cst_uint_power (gfc_se * se, tree lhs, tree rhs) tree vartmp_odd[POWI_TABLE_SIZE], vartmp_even[POWI_TABLE_SIZE]; /* Anything ** 0 is one. */ - if (tree_int_cst_sgn (rhs) == 0) + if (integer_zerop (rhs)) { se->expr = build_int_cst (type, 1); return 1; } - if (!wi::fits_shwi_p (wrhs)) + if (!wi::fits_uhwi_p (wrhs)) return 0; n = wrhs.to_uhwi (); @@ -3641,19 +3641,18 @@ gfc_conv_cst_uint_power (gfc_se * se, tree lhs, tree rhs) tmp, build_int_cst (type, 1)); lhs_prec = TYPE_PRECISION (type); - rhs_prec = TYPE_PRECISION (TREE_TYPE(rhs)); + rhs_prec = TYPE_PRECISION (TREE_TYPE (rhs)); - if (rhs_prec >= lhs_prec) + if (rhs_prec >= lhs_prec && lhs_prec <= HOST_BITS_PER_WIDE_INT) { - unsigned HOST_WIDE_INT mask; - mask = (((unsigned HOST_WIDE_INT) 1) << (lhs_prec - 1)) - 1; + unsigned HOST_WIDE_INT mask = (HOST_WIDE_INT_1U << (lhs_prec - 1)) - 1; n_odd = n & mask; } else n_odd = n; memset (vartmp_odd, 0, sizeof (vartmp_odd)); - vartmp_odd[0] = build_int_cst(type, 1); + vartmp_odd[0] = build_int_cst (type, 1); vartmp_odd[1] = lhs; odd_branch = gfc_conv_powi (se, n_odd, vartmp_odd); even_branch = NULL_TREE; @@ -3665,7 +3664,7 @@ gfc_conv_cst_uint_power (gfc_se * se, tree lhs, tree rhs) if (n_odd != n) { memset (vartmp_even, 0, sizeof (vartmp_even)); - vartmp_even[0] = build_int_cst(type, 1); + vartmp_even[0] = build_int_cst (type, 1); vartmp_even[1] = lhs; even_branch = gfc_conv_powi (se, n, vartmp_even); } |