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| author | Jakub Jelinek <jakub@redhat.com> | 2020-02-13 10:04:11 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2020-02-13 10:04:11 +0100 |
| commit | 8aba425f4ebc5e2c054776d3cdddf13f7c1918f8 (patch) | |
| tree | b99f04913cac6d23c8d1bccea47a2a03a9d44c98 /gcc/fold-const.h | |
| parent | 8ea884b85e338d09b14e6a54043c53ae0c1b1fe9 (diff) | |
| download | gcc-8aba425f4ebc5e2c054776d3cdddf13f7c1918f8.zip gcc-8aba425f4ebc5e2c054776d3cdddf13f7c1918f8.tar.gz gcc-8aba425f4ebc5e2c054776d3cdddf13f7c1918f8.tar.bz2 | |
sccvn: Handle bitfields in vn_reference_lookup_3 [PR93582]
The following patch is first step towards fixing PR93582.
vn_reference_lookup_3 right now punts on anything that isn't byte aligned,
so to be able to lookup a constant bitfield store, one needs to use
the exact same COMPONENT_REF, otherwise it isn't found.
This patch lifts up that that restriction if the bits to be loaded are
covered by a single store of a constant (keeps the restriction so far
for the multiple store case, can tweak that incrementally, but I think
for bisection etc. it is worth to do it one step at a time).
2020-02-13 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/93582
* fold-const.h (shift_bytes_in_array_left,
shift_bytes_in_array_right): Declare.
* fold-const.c (shift_bytes_in_array_left,
shift_bytes_in_array_right): New function, moved from
gimple-ssa-store-merging.c, no longer static.
* gimple-ssa-store-merging.c (shift_bytes_in_array): Move
to gimple-ssa-store-merging.c and rename to shift_bytes_in_array_left.
(shift_bytes_in_array_right): Move to gimple-ssa-store-merging.c.
(encode_tree_to_bitpos): Use shift_bytes_in_array_left instead of
shift_bytes_in_array.
(verify_shift_bytes_in_array): Rename to ...
(verify_shift_bytes_in_array_left): ... this. Use
shift_bytes_in_array_left instead of shift_bytes_in_array.
(store_merging_c_tests): Call verify_shift_bytes_in_array_left
instead of verify_shift_bytes_in_array.
* tree-ssa-sccvn.c (vn_reference_lookup_3): For native_encode_expr
/ native_interpret_expr where the store covers all needed bits,
punt on PDP-endian, otherwise allow all involved offsets and sizes
not to be byte-aligned.
* gcc.dg/tree-ssa/pr93582-1.c: New test.
* gcc.dg/tree-ssa/pr93582-2.c: New test.
* gcc.dg/tree-ssa/pr93582-3.c: New test.
Diffstat (limited to 'gcc/fold-const.h')
| -rw-r--r-- | gcc/fold-const.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/gcc/fold-const.h b/gcc/fold-const.h index 7ac792f..0f788a4 100644 --- a/gcc/fold-const.h +++ b/gcc/fold-const.h @@ -30,6 +30,10 @@ extern int native_encode_initializer (tree, unsigned char *, int, int off = -1); extern tree native_interpret_expr (tree, const unsigned char *, int); extern bool can_native_interpret_type_p (tree); +extern void shift_bytes_in_array_left (unsigned char *, unsigned int, + unsigned int); +extern void shift_bytes_in_array_right (unsigned char *, unsigned int, + unsigned int); /* Fold constants as much as possible in an expression. Returns the simplified expression. |