From: Andrew Pinski <apin...@marvell.com>
This is a new version of the patch to fix PR 102216.
Instead of doing the canonicalization inside forwprop, Richi
mentioned we should do it inside fold_stmt_1 and that is what
this patch does.
PR tree-optimization/102216
gcc/ChangeLog:
* gimple-fold.c (fold_stmt_1): Add canonicalization
of "&MEM[ssa_n, CST]" to "ssa_n p+ CST", note this
can only be done if !in_place.
gcc/testsuite/ChangeLog:
* g++.dg/tree-ssa/pr102216-1.C: New test.
* g++.dg/tree-ssa/pr102216-2.C: New test.
---
gcc/gimple-fold.c | 21 ++++++++++
gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C | 21 ++++++++++
gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C | 45 ++++++++++++++++++++++
3 files changed, 87 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C
create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index ad9703ee471..aab6818c93f 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -6061,6 +6061,27 @@ fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace,
tree (*valueize) (tree))
if (REFERENCE_CLASS_P (*lhs)
&& maybe_canonicalize_mem_ref_addr (lhs))
changed = true;
+ /* Canonicalize &MEM[ssa_n, CST] to ssa_n p+ CST.
+ This cannot be done in maybe_canonicalize_mem_ref_addr
+ as the gimple now has two operands rather than one.
+ The same reason why this can't be done in
+ maybe_canonicalize_mem_ref_addr is the same reason why
+ this can't be done inplace. */
+ if (!inplace && TREE_CODE (*rhs) == ADDR_EXPR)
+ {
+ tree inner = TREE_OPERAND (*rhs, 0);
+ if (TREE_CODE (inner) == MEM_REF
+ && TREE_CODE (TREE_OPERAND (inner, 0)) == SSA_NAME
+ && TREE_CODE (TREE_OPERAND (inner, 1)) == INTEGER_CST)
+ {
+ tree ptr = TREE_OPERAND (inner, 0);
+ tree addon = TREE_OPERAND (inner, 1);
+ addon = fold_convert (sizetype, addon);
+ gimple_assign_set_rhs_with_ops (gsi, POINTER_PLUS_EXPR,
+ ptr, addon);
+ changed = true;
+ }
+ }
}
else
{
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C
b/gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C
new file mode 100644
index 00000000000..21f7f6797ff
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C
@@ -0,0 +1,21 @@
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+void link_error ();
+void g ()
+{
+ const char **language_names;
+
+ language_names = new const char *[6];
+
+ const char **language_names_p = language_names;
+
+ language_names_p++;
+ language_names_p++;
+ language_names_p++;
+
+ if ( (language_names_p) - (language_names+3) != 0)
+ link_error();
+ delete[] language_names;
+}
+/* We should have removed the link_error on the gimple level as GCC should
+ be able to tell that language_names_p is the same as language_names+3. */
+/* { dg-final { scan-tree-dump-times "link_error" 0 "optimized" } } */
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C
b/gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C
new file mode 100644
index 00000000000..8d351a9bad0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C
@@ -0,0 +1,45 @@
+/* { dg-options "-O2 -Wall" } */
+#include <algorithm>
+
+static inline bool
+compare_cstrings (const char *str1, const char *str2)
+{
+ return str1 < str2;
+}
+
+void
+add_set_language_command ()
+{
+ static const char **language_names;
+
+ language_names = new const char *[6];
+
+ language_names[0] = "auto";
+ language_names[1] = "local";
+ language_names[2] = "unknown";
+
+ const char **language_names_p = language_names;
+ /* language_names_p == &language_names[0]. */
+ language_names_p++;
+ /* language_names_p == &language_names[1]. */
+ language_names_p++;
+ /* language_names_p == &language_names[2]. */
+ language_names_p++;
+ /* language_names_p == &language_names[3]. */
+
+ const char **sort_begin;
+
+ if (0)
+ sort_begin = &language_names[3];
+ else
+ sort_begin = language_names_p;
+
+ language_names[3] = "";
+ language_names[4] = "";
+ language_names[5] = NULL;
+
+ /* There should be no warning associated with this std::sort as
+ sort_begin != &language_names[5] and GCC should be able to figure
+ that out. */
+ std::sort (sort_begin, &language_names[5], compare_cstrings);
+}
--
2.17.1
