tree-ssa-sccvn.c (vn_reference_lookup_3): Avoid redundant lookups, make looking throu...

2011-08-11  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-sccvn.c (vn_reference_lookup_3): Avoid redundant
	lookups, make looking through aggregate copies stronger.

	* g++.dg/tree-ssa/pr41186.C: Un-XFAIL.

From-SVN: r177672

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e7ed90d3d52d7ef114649f9b58f2b15fd31649a2..c2c62bc5f21c96bbdb7a6b5cf24e6f45a85a7e5a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2011-08-11  Richard Guenther  <rguenther@suse.de>
+
+       * tree-ssa-sccvn.c (vn_reference_lookup_3): Avoid redundant
+       lookups, make looking through aggregate copies stronger.
+
 2011-08-11  Richard Henderson  <rth@redhat.com>
 
        PR bootstrap/50018

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d515387829bb95ecbc532f5cf43fd16ab4175b24..8c1dcfd7b4f6bedf28cd717b489bb0178e0031e0 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2011-08-11  Richard Guenther  <rguenther@suse.de>
+
+       * g++.dg/tree-ssa/pr41186.C: Un-XFAIL.
+
 2011-08-11  Michael Matz  <matz@suse.de>
 
        * gcc.dg/graphite/run-id-pr47593.c: Remove -m32.

diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr41186.C b/gcc/testsuite/g++.dg/tree-ssa/pr41186.C
index 8739ae9e6d5f74d304084fec48ac45ce2451c1cd..cc685b207f1c80da3e4561b1042022f128dcd0db 100644 (file)
--- a/gcc/testsuite/g++.dg/tree-ssa/pr41186.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr41186.C
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O -fdump-tree-fre1-details" } */
+/* { dg-options "-O -fno-tree-sra -fdump-tree-fre1-details" } */
 
 struct Foo {
   Foo() {};
@@ -30,6 +30,6 @@ int main()
 }
 
 /* { dg-final { scan-tree-dump "Replaced b1.b with 1" "fre1" } } */
-/* { dg-final { scan-tree-dump "Replaced b1.i with 0" "fre1" { xfail *-*-* } } } */
-/* { dg-final { scan-tree-dump "Replaced b1.f with 1" "fre1" { xfail *-*-* } } } */
+/* { dg-final { scan-tree-dump "Replaced b1.D.\[0-9\]*.i with 0" "fre1" } } */
+/* { dg-final { scan-tree-dump "Replaced b1.D.\[0-9\]*.f with 1" "fre1" } } */
 /* { dg-final { cleanup-tree-dump "fre1" } } */

diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index 7cf6123335be38e2514b017062426b2f8516ff1b..d65b9ebe9c26a1f9e350f1675ca29db1cd26ca58 100644 (file)
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -1351,17 +1351,27 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
     {
       VEC (vn_reference_op_s, heap) *tem;
       tree lhs = gimple_assign_lhs (def_stmt);
+      bool valueized_anything = false;
       /* Avoid re-allocation overhead.  */
       VEC_truncate (vn_reference_op_s, lhs_ops, 0);
       copy_reference_ops_from_ref (lhs, &lhs_ops);
       tem = lhs_ops;
-      lhs_ops = valueize_refs (lhs_ops);
+      lhs_ops = valueize_refs_1 (lhs_ops, &valueized_anything);
       gcc_assert (lhs_ops == tem);
-      lhs_ref_ok = ao_ref_init_from_vn_reference (&lhs_ref, get_alias_set (lhs),
-                                                 TREE_TYPE (lhs), lhs_ops);
-      if (lhs_ref_ok
-         && !refs_may_alias_p_1 (ref, &lhs_ref, true))
-       return NULL;
+      if (valueized_anything)
+       {
+         lhs_ref_ok = ao_ref_init_from_vn_reference (&lhs_ref,
+                                                     get_alias_set (lhs),
+                                                     TREE_TYPE (lhs), lhs_ops);
+         if (lhs_ref_ok
+             && !refs_may_alias_p_1 (ref, &lhs_ref, true))
+           return NULL;
+       }
+      else
+       {
+         ao_ref_init (&lhs_ref, lhs);
+         lhs_ref_ok = true;
+       }
     }
 
   base = ao_ref_base (ref);
@@ -1469,6 +1479,20 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
          j--;
        }
 
+      /* ???  The innermost op should always be a MEM_REF and we already
+         checked that the assignment to the lhs kills vr.  Thus for
+        aggregate copies using char[] types the vn_reference_op_eq
+        may fail when comparing types for compatibility.  But we really
+        don't care here - further lookups with the rewritten operands
+        will simply fail if we messed up types too badly.  */
+      if (j == 0 && i == 0
+         && VEC_index (vn_reference_op_s, lhs_ops, 0)->opcode == MEM_REF
+         && VEC_index (vn_reference_op_s, vr->operands, i)->opcode == MEM_REF
+         && tree_int_cst_equal
+              (VEC_index (vn_reference_op_s, lhs_ops, 0)->op0,
+               VEC_index (vn_reference_op_s, vr->operands, i)->op0))
+       i--, j--;
+
       /* i now points to the first additional op.
         ???  LHS may not be completely contained in VR, one or more
         VIEW_CONVERT_EXPRs could be in its way.  We could at least