This makes sure to handle MEM[p + 4] and MEM[p].j with j at offset 4
as the same ref in store motion. For hashing we need to be
more restrictive in what we handle since there's no poly-int
handlers for inchash. For comparison we can compare poly_offsets directly.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
2021-07-02 Richard Biener <rguent...@suse.de>
PR tree-optimization/101293
* tree-ssa-loop-im.c (mem_ref_hasher::equal): Compare MEM_REF bases
with combined offsets.
(gather_mem_refs_stmt): Hash MEM_REFs as if their offset were
combined with the rest of the offset.
* gcc.dg/tree-ssa/ssa-lim-15.c: New testcase.
---
gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-15.c | 18 +++++++++++++++
gcc/tree-ssa-loop-im.c | 27 ++++++++++++++++++----
2 files changed, 41 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-15.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-15.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-15.c
new file mode 100644
index 00000000000..5efb95627ee
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-15.c
@@ -0,0 +1,18 @@
+/* PR/101293 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-lim2-details" } */
+
+struct X { int i; int j; };
+
+void foo(struct X *x, int n)
+{
+ for (int i = 0; i < n; ++i)
+ {
+ int *p = &x->j;
+ int tem = *p;
+ x->j += tem * i;
+ }
+}
+
+/* Make sure LIM can handle unifying MEM[x, 4] and MEM[x].j */
+/* { dg-final { scan-tree-dump "Executing store motion" "lim2" } } */
diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c
index 48c952a1eac..e7a3050ba9d 100644
--- a/gcc/tree-ssa-loop-im.c
+++ b/gcc/tree-ssa-loop-im.c
@@ -194,8 +194,14 @@ mem_ref_hasher::equal (const im_mem_ref *mem1, const
ao_ref *obj2)
{
if (obj2->max_size_known_p ())
return (mem1->ref_decomposed
- && operand_equal_p (mem1->mem.base, obj2->base, 0)
- && known_eq (mem1->mem.offset, obj2->offset)
+ && ((TREE_CODE (mem1->mem.base) == MEM_REF
+ && TREE_CODE (obj2->base) == MEM_REF
+ && operand_equal_p (TREE_OPERAND (mem1->mem.base, 0),
+ TREE_OPERAND (obj2->base, 0), 0)
+ && known_eq (mem_ref_offset (mem1->mem.base) * BITS_PER_UNIT +
mem1->mem.offset,
+ mem_ref_offset (obj2->base) * BITS_PER_UNIT +
obj2->offset))
+ || (operand_equal_p (mem1->mem.base, obj2->base, 0)
+ && known_eq (mem1->mem.offset, obj2->offset)))
&& known_eq (mem1->mem.size, obj2->size)
&& known_eq (mem1->mem.max_size, obj2->max_size)
&& mem1->mem.volatile_p == obj2->volatile_p
@@ -1500,8 +1506,21 @@ gather_mem_refs_stmt (class loop *loop, gimple *stmt)
&& (mem_base = get_addr_base_and_unit_offset (aor.ref, &mem_off)))
{
ref_decomposed = true;
- hash = iterative_hash_expr (ao_ref_base (&aor), 0);
- hash = iterative_hash_host_wide_int (offset, hash);
+ tree base = ao_ref_base (&aor);
+ poly_int64 moffset;
+ HOST_WIDE_INT mcoffset;
+ if (TREE_CODE (base) == MEM_REF
+ && (mem_ref_offset (base) * BITS_PER_UNIT + offset).to_shwi
(&moffset)
+ && moffset.is_constant (&mcoffset))
+ {
+ hash = iterative_hash_expr (TREE_OPERAND (base, 0), 0);
+ hash = iterative_hash_host_wide_int (mcoffset, hash);
+ }
+ else
+ {
+ hash = iterative_hash_expr (base, 0);
+ hash = iterative_hash_host_wide_int (offset, hash);
+ }
hash = iterative_hash_host_wide_int (size, hash);
}
else
--
2.26.2
