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| author | Andrew Pinski <apinski@marvell.com> | 2020-01-16 07:54:51 +0000 |
|---|---|---|
| committer | Andrew Pinski <apinski@marvell.com> | 2020-01-16 12:34:32 +0000 |
| commit | 2db99ef7896914bfbca1adc40f6ac4ba8887f040 (patch) | |
| tree | 80b5d90546ab599c47967b969c77574cba2ea581 /gcc/tree-ssa-sccvn.c | |
| parent | 7c6056d52ef7ea43b503b11a571b316d55f392c7 (diff) | |
| download | gcc-2db99ef7896914bfbca1adc40f6ac4ba8887f040.zip gcc-2db99ef7896914bfbca1adc40f6ac4ba8887f040.tar.gz gcc-2db99ef7896914bfbca1adc40f6ac4ba8887f040.tar.bz2 | |
Fix value numbering dealing with reverse byte order
Hi,
While working on bit-field lowering pass, I came across this bug.
The IR looks like:
VIEW_CONVERT_EXPR<unsigned long>(var1) = _12;
_1 = BIT_FIELD_REF <var1, 64, 0>;
Where the BIT_FIELD_REF has REF_REVERSE_STORAGE_ORDER set on it
and var1's type has TYPE_REVERSE_STORAGE_ORDER set on it.
PRE/FRE would decided to prop _12 into the BFR statement
which would produce wrong code.
And yes _12 has the correct byte order already; bit-field lowering
removes the implicit byte swaps in the IR and adds the explicity
to make it easier optimize later on.
This patch adds a check for storage_order_barrier_p on the lhs tree
which returns true in the case where we had a reverse order with a VCE.
ChangeLog:
* tree-ssa-sccvn.c(vn_reference_lookup_3): Check lhs for
!storage_order_barrier_p.
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 3b27c50..4d13015 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -2593,6 +2593,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_, &offset2, &size2, &maxsize2, &reverse); if (base2 && !reverse + && !storage_order_barrier_p (lhs) && known_eq (maxsize2, size2) && multiple_p (size2, BITS_PER_UNIT) && multiple_p (offset2, BITS_PER_UNIT) @@ -2695,6 +2696,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_, &offset2, &size2, &maxsize2, &reverse); tree def_rhs = gimple_assign_rhs1 (def_stmt); if (!reverse + && !storage_order_barrier_p (lhs) && known_size_p (maxsize2) && known_eq (maxsize2, size2) && adjust_offsets_for_equal_base_address (base, &offset, |