On 20/10/2023 14:41, Richard Biener wrote:
On Fri, 20 Oct 2023, Andre Vieira (lists) wrote:
Hi,
This patch stops lowering of bitfields by ifcvt when they have non-constant
offsets as we are not likely to be able to do anything useful with those
during
vectorization. That also fixes the issue reported in PR 111882, which was
being caused by an offset with a side-effect being lowered, but constants have
no side-effects so we will no longer run into that problem.
Bootstrapped and regression tested on aarch64-unknown-linux-gnu.
OK for trunk?
+ if (!TREE_CONSTANT (DECL_FIELD_OFFSET (rep_decl))
+ || !TREE_CONSTANT (DECL_FIELD_BIT_OFFSET (rep_decl))
+ || !TREE_CONSTANT (ref_offset)
+ || !TREE_CONSTANT (DECL_FIELD_BIT_OFFSET (field_decl)))
+ return NULL_TREE;
DECL_FIELD_BIT_OFFSET is always constant. Please test
TREE_CODE (..) == INTEGER_CST instead of TREE_CONSTANT.
OK with those changes.
After I sent it I realized it would've been nicer to add a diagnostic,
you OK with:
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "\t Bitfield NOT OK to lower,"
+ " offset is non-constant.\n");
Richard.
gcc/ChangeLog:
PR tree-optimization/111882
* tree-if-conv.cc (get_bitfield_rep): Return NULL_TREE for bitfields
with
non-constant offsets.
gcc/testsuite/ChangeLog:
* gcc.dg/vect/pr111882.c: New test.
