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| author | Richard Sandiford <richard.sandiford@arm.com> | 2019-07-29 18:50:25 +0000 |
|---|---|---|
| committer | Richard Sandiford <rsandifo@gcc.gnu.org> | 2019-07-29 18:50:25 +0000 |
| commit | 5d5bb9bc26bbd714ef81a7eb91e77e312582ccdc (patch) | |
| tree | 83bf374fb969d0c189428c6b47e87b52b4cff13f /gcc | |
| parent | 5c6aa9a8919cbf0dcf3c375f51012720bfb5f3a1 (diff) | |
| download | gcc-5d5bb9bc26bbd714ef81a7eb91e77e312582ccdc.zip gcc-5d5bb9bc26bbd714ef81a7eb91e77e312582ccdc.tar.gz gcc-5d5bb9bc26bbd714ef81a7eb91e77e312582ccdc.tar.bz2 | |
Fix inchash handling of wide_ints (PR91242)
inchash::hash::add_wide_int operated directly on the raw encoding
of the wide_int, including any redundant upper bits. The problem
with that is that the upper bits are only defined for some wide-int
storage types (including wide_int itself). wi::to_wide(tree) instead
returns a value that is extended according to the signedness of the
type (so that wi::to_widest can use the same encoding) while rtxes
have the awkward special case of BI, which can be zero-extended
rather than sign-extended.
In the PR, we computed a hash for a "normal" sign-extended wide_int
while the existing entries hashed wi::to_wide(tree). This gives
different results for unsigned types that have the top bit set.
The patch fixes that by hashing the canonical sign-extended form even
if the raw encoding happens to be different.
2019-07-29 Richard Sandiford <richard.sandiford@arm.com>
gcc/
* wide-int.h (generic_wide_int::sext_elt): New function.
* inchash.h (hash::add_wide_int): Use it instead of elt.
From-SVN: r273881
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/inchash.h | 2 | ||||
| -rw-r--r-- | gcc/wide-int.h | 18 |
3 files changed, 24 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2d981f6..7f3dfa7 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2019-07-29 Richard Sandiford <richard.sandiford@arm.com> + + * wide-int.h (generic_wide_int::sext_elt): New function. + * inchash.h (hash::add_wide_int): Use it instead of elt. + 2019-07-29 Kyrylo Tkachov <kyrylo.tkachov@arm.com> * config/arm/arm-builtins.c (acle_builtin_data): Expand VAR1 to diff --git a/gcc/inchash.h b/gcc/inchash.h index f61e631..56588d2 100644 --- a/gcc/inchash.h +++ b/gcc/inchash.h @@ -85,7 +85,7 @@ class hash { add_int (x.get_len ()); for (unsigned i = 0; i < x.get_len (); i++) - add_hwi (x.elt (i)); + add_hwi (x.sext_elt (i)); } /* Hash in pointer PTR. */ diff --git a/gcc/wide-int.h b/gcc/wide-int.h index 6c816cc..862079a 100644 --- a/gcc/wide-int.h +++ b/gcc/wide-int.h @@ -730,6 +730,7 @@ public: /* Public accessors for the interior of a wide int. */ HOST_WIDE_INT sign_mask () const; HOST_WIDE_INT elt (unsigned int) const; + HOST_WIDE_INT sext_elt (unsigned int) const; unsigned HOST_WIDE_INT ulow () const; unsigned HOST_WIDE_INT uhigh () const; HOST_WIDE_INT slow () const; @@ -909,6 +910,23 @@ generic_wide_int <storage>::elt (unsigned int i) const return this->get_val ()[i]; } +/* Like elt, but sign-extend beyond the upper bit, instead of returning + the raw encoding. */ +template <typename storage> +inline HOST_WIDE_INT +generic_wide_int <storage>::sext_elt (unsigned int i) const +{ + HOST_WIDE_INT elt_i = elt (i); + if (!is_sign_extended) + { + unsigned int precision = this->get_precision (); + unsigned int lsb = i * HOST_BITS_PER_WIDE_INT; + if (precision - lsb < HOST_BITS_PER_WIDE_INT) + elt_i = sext_hwi (elt_i, precision - lsb); + } + return elt_i; +} + template <typename storage> template <typename T> inline generic_wide_int <storage> & |