[PR 80622] Treat const pools as initialized in SRA

2017-05-04  Martin Jambor  <mjambor@suse.cz>

	PR tree-optimization/80622
	* tree-sra.c (comes_initialized_p): New function.
	(build_accesses_from_assign): Only set write lazily when
	comes_initialized_p is false.
	(analyze_access_subtree): Use comes_initialized_p.
	(propagate_subaccesses_across_link): Assert !comes_initialized_p
	instead of testing for PARM_DECL.

testsuite/
	* gcc.dg/tree-ssa/pr80622.c: New test.

From-SVN: r247604

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 34a56ab17c626a7fc4d99edec0dc6ca4c99c467a..a59b8227ee31a31ffc9ca12833f02f3ecf5874b8 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,4 +1,14 @@
-2016-05-04  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+2017-05-04  Martin Jambor  <mjambor@suse.cz>
+
+       PR tree-optimization/80622
+       * tree-sra.c (comes_initialized_p): New function.
+       (build_accesses_from_assign): Only set write lazily when
+       comes_initialized_p is false.
+       (analyze_access_subtree): Use comes_initialized_p.
+       (propagate_subaccesses_across_link): Assert !comes_initialized_p
+       instead of testing for PARM_DECL.
+
+2017-05-04  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
        * config/aarch64/aarch64.md (prefetch); Adjust predicate and
        constraint on operand 0 to allow more general addressing modes.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b8d1e2f3cb3aaf41db59f8a48e31f2e4fc083235..feb65d55f5320e4f6384cfcf3f1069c424180dd0 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,4 +1,9 @@
-2016-05-04  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+2017-05-04  Martin Jambor  <mjambor@suse.cz>
+
+       PR tree-optimization/80622
+       * gcc.dg/tree-ssa/pr80622.c: New test.
+
+2017-05-04  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
        * gcc.target/aarch64/prfm_imm_offset_1.c: New test.
 

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr80622.c b/gcc/testsuite/gcc.dg/tree-ssa/pr80622.c
new file mode 100644 (file)
index 0000000..96dcb8f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr80622.c
@@ -0,0 +1,19 @@
+/* { dg-do run } */
+/* { dg-options "-O" } */
+
+struct S { int d; char e; int f; char g; } a;
+char c;
+
+int
+main ()
+{
+  struct S b[][1] = {3, 0, 3, 4, 3, 0, 3, 4, 3, 0, 3, 4, 3, 0, 3, 4, 3,
+                      0, 3, 4, 3, 0, 3, 4, 3, 0, 3, 4, 3, 0, 3, 4, 3, 0,
+                      3, 4, 3, 4, 7, 7, 3, 5, 0, 3, 4, 7, 7, 3, 5, 0, 3,
+                      4, 3, 4, 7, 7, 3, 5, 0, 3, 4, 7, 7, 3, 5, 0, 3, 4};
+  a = b[4][0];
+  c = b[4][0].e;
+  if (a.g != 4)
+    __builtin_abort ();
+  return 0;
+}

diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 1606573aeadcf3d3901493d39b5ba4c3d37aa35e..8ac9c0783ff0988417fcb0edcebfa101bb009e65 100644 (file)
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -1305,6 +1305,15 @@ disqualify_if_bad_bb_terminating_stmt (gimple *stmt, tree lhs, tree rhs)
   return false;
 }
 
+/* Return true if the nature of BASE is such that it contains data even if
+   there is no write to it in the function.  */
+
+static bool
+comes_initialized_p (tree base)
+{
+  return TREE_CODE (base) == PARM_DECL || constant_decl_p (base);
+}
+
 /* Scan expressions occurring in STMT, create access structures for all accesses
    to candidates for scalarization and remove those candidates which occur in
    statements or expressions that prevent them from being split apart.  Return
@@ -1364,8 +1373,10 @@ build_accesses_from_assign (gimple *stmt)
       link->racc = racc;
       add_link_to_rhs (racc, link);
       /* Let's delay marking the areas as written until propagation of accesses
-        across link.  */
-      lacc->write = false;
+        across link, unless the nature of rhs tells us that its data comes
+        from elsewhere.  */
+      if (!comes_initialized_p (racc->base))
+       lacc->write = false;
     }
 
   return lacc || racc;
@@ -2472,8 +2483,7 @@ analyze_access_subtree (struct access *root, struct access *parent,
 
   if (!hole || root->grp_total_scalarization)
     root->grp_covered = 1;
-  else if (root->grp_write || TREE_CODE (root->base) == PARM_DECL
-          || constant_decl_p (root->base))
+  else if (root->grp_write || comes_initialized_p (root->base))
     root->grp_unscalarized_data = 1; /* not covered and written to */
   return sth_created;
 }
@@ -2581,11 +2591,14 @@ propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
 
   /* IF the LHS is still not marked as being written to, we only need to do so
      if the RHS at this level actually was.  */
-  if (!lacc->grp_write &&
-      (racc->grp_write || TREE_CODE (racc->base) == PARM_DECL))
+  if (!lacc->grp_write)
     {
-      lacc->grp_write = true;
-      ret = true;
+      gcc_checking_assert (!comes_initialized_p (racc->base));
+      if (racc->grp_write)
+       {
+         lacc->grp_write = true;
+         ret = true;
+       }
     }
 
   if (is_gimple_reg_type (lacc->type)