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authorRichard Biener <rguenther@suse.de>2017-10-24 13:51:45 +0000
committerRichard Biener <rguenth@gcc.gnu.org>2017-10-24 13:51:45 +0000
commitda76b2532f85d0e928862303b1fc92fa2a5a6138 (patch)
treef72cf1f121e8ed72233293ec677e54a9f8894541
parenteab01c18fdf287aaac60224ddbecae6574631b7b (diff)
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re PR tree-optimization/82697 (Wrong optimization with aliasing and "if")
2017-10-24 Richard Biener <rguenther@suse.de> PR tree-optimization/82697 * tree-ssa-phiopt.c (cond_store_replacement): Use alias-set zero for conditional load and unconditional store. * gcc.dg/torture/pr82697.c: New testcase. From-SVN: r254047
-rw-r--r--gcc/ChangeLog6
-rw-r--r--gcc/testsuite/ChangeLog5
-rw-r--r--gcc/testsuite/gcc.dg/torture/pr82697.c23
-rw-r--r--gcc/tree-ssa-phiopt.c17
4 files changed, 50 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ce02caa..63bb64f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-24 Richard Biener <rguenther@suse.de>
+
+ PR tree-optimization/82697
+ * tree-ssa-phiopt.c (cond_store_replacement): Use alias-set
+ zero for conditional load and unconditional store.
+
2017-10-24 H.J. Lu <hongjiu.lu@intel.com>
* doc/install.texi: Document bootstrap-cet.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a8a4a11..18794e4 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-10-24 Richard Biener <rguenther@suse.de>
+
+ PR tree-optimization/82697
+ * gcc.dg/torture/pr82697.c: New testcase.
+
2017-10-24 Mukesh Kapoor <mukesh.kapoor@oracle.com>
Paolo Carlini <paolo.carlini@oracle.com>
diff --git a/gcc/testsuite/gcc.dg/torture/pr82697.c b/gcc/testsuite/gcc.dg/torture/pr82697.c
new file mode 100644
index 0000000..57da8a2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr82697.c
@@ -0,0 +1,23 @@
+/* { dg-do run } */
+
+__attribute__((noinline,noclone))
+void test(int *pi, long *pl, int f)
+{
+ *pl = 0;
+
+ *pi = 1;
+
+ if (f)
+ *pl = 2;
+}
+
+int main()
+{
+ void *p = __builtin_malloc(sizeof (long));
+
+ test(p, p, 0);
+
+ if (*(int *)p != 1)
+ __builtin_abort ();
+ return 0;
+}
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index d0570c3..6e0e186 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -1912,9 +1912,24 @@ cond_store_replacement (basic_block middle_bb, basic_block join_bb,
gsi_remove (&gsi, true);
release_defs (assign);
+ /* Make both store and load use alias-set zero as we have to
+ deal with the case of the store being a conditional change
+ of the dynamic type. */
+ lhs = unshare_expr (lhs);
+ tree *basep = &lhs;
+ while (handled_component_p (*basep))
+ basep = &TREE_OPERAND (*basep, 0);
+ if (TREE_CODE (*basep) == MEM_REF
+ || TREE_CODE (*basep) == TARGET_MEM_REF)
+ TREE_OPERAND (*basep, 1)
+ = fold_convert (ptr_type_node, TREE_OPERAND (*basep, 1));
+ else
+ *basep = build2 (MEM_REF, TREE_TYPE (*basep),
+ build_fold_addr_expr (*basep),
+ build_zero_cst (ptr_type_node));
+
/* 2) Insert a load from the memory of the store to the temporary
on the edge which did not contain the store. */
- lhs = unshare_expr (lhs);
name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore");
new_stmt = gimple_build_assign (name, lhs);
gimple_set_location (new_stmt, locus);