DOM can handle different shape refs but fails for bases with
differing TBAA behavior currently. This isn't necessary
and fixed via using OEP_ADDRESS_OF for handling of the base
returned from get_ref_base_and_extent.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Richard.
2019-07-02 Richard Biener <rguent...@suse.de>
PR tree-optimization/58483
* tree-ssa-scopedtables.c (avail_expr_hash): Use OEP_ADDRESS_OF
for MEM_REF base hashing.
(equal_mem_array_ref_p): Likewise for base comparison.
* gcc.dg/tree-ssa/ssa-dom-cse-8.c: New testcase.
Index: gcc/tree-ssa-scopedtables.c
===================================================================
--- gcc/tree-ssa-scopedtables.c (revision 272843)
+++ gcc/tree-ssa-scopedtables.c (working copy)
@@ -494,7 +494,9 @@ avail_expr_hash (class expr_hash_elt *p)
{
enum tree_code code = MEM_REF;
hstate.add_object (code);
- inchash::add_expr (base, hstate);
+ inchash::add_expr (base, hstate,
+ TREE_CODE (base) == MEM_REF
+ ? OEP_ADDRESS_OF : 0);
hstate.add_object (offset);
hstate.add_object (size);
return hstate.end ();
@@ -540,7 +542,12 @@ equal_mem_array_ref_p (tree t0, tree t1)
if (rev0 != rev1 || maybe_ne (sz0, sz1) || maybe_ne (off0, off1))
return false;
- return operand_equal_p (base0, base1, 0);
+ return operand_equal_p (base0, base1,
+ (TREE_CODE (base0) == MEM_REF
+ || TREE_CODE (base0) == TARGET_MEM_REF)
+ && (TREE_CODE (base1) == MEM_REF
+ || TREE_CODE (base1) == TARGET_MEM_REF)
+ ? OEP_ADDRESS_OF : 0);
}
/* Compare two hashable_expr structures for equivalence. They are
Index: gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-cse-8.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-cse-8.c (nonexistent)
+++ gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-cse-8.c (working copy)
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fgimple -fdump-tree-dom2" } */
+
+int __GIMPLE (ssa,startwith("dom"))
+foo (void *p)
+{
+ int _2;
+
+ __BB(2):
+ __MEM <int> ((char *)p_1(D) + 4) = 20;
+ _2 = __MEM <const int> ((int *)p_1(D) + 4);
+ return _2;
+}
+
+/* { dg-final { scan-tree-dump "return 20;" "dom2" } } */
