Make SRA less strict with memcpy performing MEM_REFs

2019-03-10  Martin Jambor  <mjambor@suse.cz>

	PR tree-optimization/85762
	PR tree-optimization/87008
	PR tree-optimization/85459
	* tree-sra.c (contains_vce_or_bfcref_p): New parameter, set the bool
	it points to if there is a type changing MEM_REF.  Adjust all callers.
	(build_accesses_from_assign): Disable total scalarization if
	contains_vce_or_bfcref_p returns true through the new parameter, for
	both rhs and lhs.

	testsuite/
	* g++.dg/tree-ssa/pr87008.C: New test.
	* gcc.dg/guality/pr54970.c: Xfail tests querying a[0] everywhere.

From-SVN: r269556

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5b1fb49bea11cdb37e61b0c6fd33460e9de5cfad..d1e59d4886a2b8274dab270a128896310a20a6ab 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2019-03-10  Martin Jambor  <mjambor@suse.cz>
+
+       PR tree-optimization/85762
+       PR tree-optimization/87008
+       PR tree-optimization/85459
+       * tree-sra.c (contains_vce_or_bfcref_p): New parameter, set the bool
+       it points to if there is a type changing MEM_REF.  Adjust all callers.
+       (build_accesses_from_assign): Disable total scalarization if
+       contains_vce_or_bfcref_p returns true through the new parameter, for
+       both rhs and lhs.
+
 2019-03-09  Jakub Jelinek  <jakub@redhat.com>
 
        PR c/88568

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9dfdfe3baff4fe20efa6a8baf4d55e180fd3b790..b6d6f678ed4855bf2dbf974bc931684ca67eba3d 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2019-03-10  Martin Jambor  <mjambor@suse.cz>
+
+       PR tree-optimization/85762
+       PR tree-optimization/87008
+       PR tree-optimization/85459
+       * g++.dg/tree-ssa/pr87008.C: New test.
+       * gcc.dg/guality/pr54970.c: Xfail tests querying a[0] everywhere.
+
 2019-03-10  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
        PR fortran/66089

diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr87008.C b/gcc/testsuite/g++.dg/tree-ssa/pr87008.C
new file mode 100644 (file)
index 0000000..eef521f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr87008.C
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+extern void dontcallthis();
+
+struct A { long a, b; };
+struct B : A {};
+template<class T>void cp(T&a,T const&b){a=b;}
+long f(B x){
+  B y; cp<A>(y,x);
+  B z; cp<A>(z,x);
+  if (y.a - z.a)
+    dontcallthis ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-not "dontcallthis" "optimized" } } */

diff --git a/gcc/testsuite/gcc.dg/guality/pr54970.c b/gcc/testsuite/gcc.dg/guality/pr54970.c
index 5d32af07c32d6e7ca195d303622eac6d023a781a..2e0bc5784a9812e0c8d0846d558a215ba5eacd25 100644 (file)
--- a/gcc/testsuite/gcc.dg/guality/pr54970.c
+++ b/gcc/testsuite/gcc.dg/guality/pr54970.c
@@ -8,17 +8,17 @@
 int
 main ()
 {
-  int a[] = { 1, 2, 3 };       /* { dg-final { gdb-test .+4 "a\[0\]" "1" } } */
+  int a[] = { 1, 2, 3 };       /* { dg-final { gdb-test .+4 "a\[0\]" "1" { xfail { *-*-* } } } } */
   int *p = a + 2;              /* { dg-final { gdb-test .+3 "a\[1\]" "2" } } */
   int *q = a + 1;              /* { dg-final { gdb-test .+2 "a\[2\]" "3" } } */
                                /* { dg-final { gdb-test .+1 "*p" "3" } } */
   asm volatile (NOP);          /* { dg-final { gdb-test . "*q" "2" } } */
-  *p += 10;                    /* { dg-final { gdb-test .+4 "a\[0\]" "1" } } */
+  *p += 10;                    /* { dg-final { gdb-test .+4 "a\[0\]" "1" { xfail { *-*-* } } } } */
                                /* { dg-final { gdb-test .+3 "a\[1\]" "2" } } */
                                /* { dg-final { gdb-test .+2 "a\[2\]" "13" } } */
                                /* { dg-final { gdb-test .+1 "*p" "13" } } */
   asm volatile (NOP);          /* { dg-final { gdb-test . "*q" "2" } } */
-  *q += 10;                    /* { dg-final { gdb-test .+4 "a\[0\]" "1" } } */
+  *q += 10;                    /* { dg-final { gdb-test .+4 "a\[0\]" "1" { xfail { *-*-* } } } } */
                                /* { dg-final { gdb-test .+3 "a\[1\]" "12" } } */
                                /* { dg-final { gdb-test .+2 "a\[2\]" "13" } } */
                                /* { dg-final { gdb-test .+1 "*p" "13" } } */

diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index eeef31ba496018ca81baa14ea49b7c9327c11657..ca3858d5fc71a03587aaba806423ab88a0b30a39 100644 (file)
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -1150,29 +1150,36 @@ contains_view_convert_expr_p (const_tree ref)
   return false;
 }
 
-/* Return true if REF contains a VIEW_CONVERT_EXPR or a MEM_REF that performs
-   type conversion or a COMPONENT_REF with a bit-field field declaration.  */
+/* Return true if REF contains a VIEW_CONVERT_EXPR or a COMPONENT_REF with a
+   bit-field field declaration.  If TYPE_CHANGING_P is non-NULL, set the bool
+   it points to will be set if REF contains any of the above or a MEM_REF
+   expression that effectively performs type conversion.  */
 
 static bool
-contains_vce_or_bfcref_p (const_tree ref)
+contains_vce_or_bfcref_p (const_tree ref, bool *type_changing_p = NULL)
 {
   while (handled_component_p (ref))
     {
       if (TREE_CODE (ref) == VIEW_CONVERT_EXPR
          || (TREE_CODE (ref) == COMPONENT_REF
              && DECL_BIT_FIELD (TREE_OPERAND (ref, 1))))
-       return true;
+       {
+         if (type_changing_p)
+           *type_changing_p = true;
+         return true;
+       }
       ref = TREE_OPERAND (ref, 0);
     }
 
-  if (TREE_CODE (ref) != MEM_REF
+  if (!type_changing_p
+      || TREE_CODE (ref) != MEM_REF
       || TREE_CODE (TREE_OPERAND (ref, 0)) != ADDR_EXPR)
     return false;
 
   tree mem = TREE_OPERAND (TREE_OPERAND (ref, 0), 0);
   if (TYPE_MAIN_VARIANT (TREE_TYPE (ref))
       != TYPE_MAIN_VARIANT (TREE_TYPE (mem)))
-    return true;
+    *type_changing_p = true;
 
   return false;
 }
@@ -1368,15 +1375,26 @@ build_accesses_from_assign (gimple *stmt)
       lacc->grp_assignment_write = 1;
       if (storage_order_barrier_p (rhs))
        lacc->grp_unscalarizable_region = 1;
+
+      if (should_scalarize_away_bitmap && !is_gimple_reg_type (lacc->type))
+       {
+         bool type_changing_p = false;
+         contains_vce_or_bfcref_p (lhs, &type_changing_p);
+         if (type_changing_p)
+           bitmap_set_bit (cannot_scalarize_away_bitmap,
+                           DECL_UID (lacc->base));
+       }
     }
 
   if (racc)
     {
       racc->grp_assignment_read = 1;
-      if (should_scalarize_away_bitmap && !gimple_has_volatile_ops (stmt)
-         && !is_gimple_reg_type (racc->type))
+      if (should_scalarize_away_bitmap && !is_gimple_reg_type (racc->type))
        {
-         if (contains_vce_or_bfcref_p (rhs))
+         bool type_changing_p = false;
+         contains_vce_or_bfcref_p (rhs, &type_changing_p);
+
+         if (type_changing_p || gimple_has_volatile_ops (stmt))
            bitmap_set_bit (cannot_scalarize_away_bitmap,
                            DECL_UID (racc->base));
          else