We were actually value-numbering two entities with different type
the same rather than just having the same representation in the
hashtable. The following fixes that by wrapping the value in a
to be inserted VIEW_CONVERT_EXPR.
Bootstrapped & tested on x86_64-unknown-linux-gnu, pushed.
Richard.
2020-01-21 Richard Biener <rguent...@suse.de>
PR tree-optimization/92328
* tree-ssa-sccvn.c (vn_reference_lookup_3): Preserve
type when value-numbering same-sized store by inserting a
VIEW_CONVERT_EXPR.
(eliminate_dom_walker::eliminate_stmt): When eliminating
a redundant store handle bit-reinterpretation of the same value.
* gcc.dg/torture/pr92328.c: New testcase.
diff --git a/gcc/testsuite/gcc.dg/torture/pr92328.c
b/gcc/testsuite/gcc.dg/torture/pr92328.c
new file mode 100644
index 00000000000..7898b9efe80
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr92328.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-ftree-pre -Wno-div-by-zero" } */
+
+int nt;
+
+void
+ja (int os)
+{
+ int *ku = &os, *id = &os;
+ unsigned int qr = 0;
+
+ for (;;)
+ {
+ if (os == *ku)
+ {
+ *id = 0;
+ qr += os != *ku;
+ id = &qr;
+ }
+
+ *id &= qr;
+
+ if (os != 0)
+ {
+ nt /= 0;
+ ku = &qr;
+ }
+ }
+}
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index 4d1301593d7..0b8ee586139 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -2712,26 +2712,30 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void
*data_,
|| known_eq (ref->size, TYPE_PRECISION (vr->type)))
&& multiple_p (ref->size, BITS_PER_UNIT))
{
- if (known_eq (ref->size, size2))
- return vn_reference_lookup_or_insert_for_pieces
- (vuse, get_alias_set (lhs), vr->type, vr->operands,
- SSA_VAL (def_rhs));
- else if (! INTEGRAL_TYPE_P (TREE_TYPE (def_rhs))
- || type_has_mode_precision_p (TREE_TYPE (def_rhs)))
+ tree val = NULL_TREE;
+ if (! INTEGRAL_TYPE_P (TREE_TYPE (def_rhs))
+ || type_has_mode_precision_p (TREE_TYPE (def_rhs)))
{
gimple_match_op op (gimple_match_cond::UNCOND,
BIT_FIELD_REF, vr->type,
SSA_VAL (def_rhs),
bitsize_int (ref->size),
bitsize_int (offset - offset2));
- tree val = vn_nary_build_or_lookup (&op);
- if (val
- && (TREE_CODE (val) != SSA_NAME
- || ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val)))
- return vn_reference_lookup_or_insert_for_pieces
- (vuse, get_alias_set (lhs), vr->type,
- vr->operands, val);
+ val = vn_nary_build_or_lookup (&op);
}
+ else if (known_eq (ref->size, size2))
+ {
+ gimple_match_op op (gimple_match_cond::UNCOND,
+ VIEW_CONVERT_EXPR, vr->type,
+ SSA_VAL (def_rhs));
+ val = vn_nary_build_or_lookup (&op);
+ }
+ if (val
+ && (TREE_CODE (val) != SSA_NAME
+ || ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val)))
+ return vn_reference_lookup_or_insert_for_pieces
+ (vuse, get_alias_set (lhs), vr->type,
+ vr->operands, val);
}
else if (maxsize.is_constant (&maxsizei)
&& maxsizei % BITS_PER_UNIT == 0
@@ -5599,7 +5603,6 @@ eliminate_dom_walker::eliminate_stmt (basic_block b,
gimple_stmt_iterator *gsi)
&& (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
|| is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
{
- tree val;
tree rhs = gimple_assign_rhs1 (stmt);
vn_reference_t vnresult;
/* ??? gcc.dg/torture/pr91445.c shows that we lookup a boolean
@@ -5640,14 +5643,22 @@ eliminate_dom_walker::eliminate_stmt (basic_block b,
gimple_stmt_iterator *gsi)
else
lookup_lhs = NULL_TREE;
}
- val = NULL_TREE;
+ tree val = NULL_TREE;
if (lookup_lhs)
val = vn_reference_lookup (lookup_lhs, gimple_vuse (stmt), VN_WALK,
&vnresult, false);
if (TREE_CODE (rhs) == SSA_NAME)
rhs = VN_INFO (rhs)->valnum;
if (val
- && operand_equal_p (val, rhs, 0))
+ && (operand_equal_p (val, rhs, 0)
+ /* Due to the bitfield lookups above we can get bit
+ interpretations of the same RHS as values here. Those
+ are redundant as well. */
+ || (TREE_CODE (val) == SSA_NAME
+ && gimple_assign_single_p (SSA_NAME_DEF_STMT (val))
+ && (val = gimple_assign_rhs1 (SSA_NAME_DEF_STMT (val)))
+ && TREE_CODE (val) == VIEW_CONVERT_EXPR
+ && TREE_OPERAND (val, 0) == rhs)))
{
/* We can only remove the later store if the former aliases
at least all accesses the later one does or if the store
