re PR tree-optimization/81741 (Misoptimisation : replacing a constant field read access by a function call)

	PR tree-optimization/81741
	PR tree-optimization/71947
	* tree-ssa-dom.c: Include tree-inline.h.
	(record_temporary_equivalences): Only record SSA_NAME = SSA_NAME
	equivalences if one is more expensive to compute than the other.
	* tree-ssa-scopedtables.h (class const_or_copies): Make
	record_const_or_copy_raw method private.
	(class avail_exprs_stack): New method simplify_binary_operation.
	* tree-ssa-scopedtables.c (avail_exprs_stack::lookup_avail_expr): Call
	avail_exprs_stack::simplify_binary_operation as needed.
	(avail_exprs_stack::simplify_binary_operation): New function.

	PR tree-optimization/81741
	PR tree-optimization/71947
	* gcc.dg/tree-ssa/pr81741.c: New test.
	* gcc.dg/tree-ssa/pr71947-7.c: New test.
	* gcc.dg/tree-ssa/pr71947-8.c: New test.
	* gcc.dg/tree-ssa/pr71947-9.c: New test.
	* gcc.dg/tree-ssa/pr71941-1.c: Tweak expected output.
	* gcc.dg/tree-ssa/pr71941-2.c: Tweak expected output.
	* gcc.dg/tree-ssa/pr71941-3.c: Tweak expected output.
	* gcc.dg/tree-ssa/20030922-2.c: xfail.

From-SVN: r251279

1 files changed, 9 insertions, 4 deletions

diff --git a/gcc/tree-ssa-scopedtables.h b/gcc/tree-ssa-scopedtables.h
index df304ae..e3d7bff 100644
--- a/gcc/tree-ssa-scopedtables.h
+++ b/gcc/tree-ssa-scopedtables.h
@@ -156,6 +156,11 @@ class avail_exprs_stack
   vec<std::pair<expr_hash_elt_t, expr_hash_elt_t> > m_stack;
   hash_table<expr_elt_hasher> *m_avail_exprs;
 
+  /* For some assignments where the RHS is a binary operator, if we know
+     a equality relationship between the operands, we may be able to compute
+     a result, even if we don't know the exact value of the operands.  */
+  tree simplify_binary_operation (gimple *, class expr_hash_elt);
+
   /* We do not allow copying this object or initializing one
      from another.  */
   avail_exprs_stack& operator= (const avail_exprs_stack&);
@@ -185,10 +190,6 @@ class const_and_copies
      may follow the value chain for the RHS.  */
   void record_const_or_copy (tree, tree);
 
-  /* Record a single const/copy pair that can be unwound.  This version
-     does not follow the value chain for the RHS.  */
-  void record_const_or_copy_raw (tree, tree, tree);
-
   /* Special entry point when we want to provide an explicit previous
      value for the first argument.  Try to get rid of this in the future. 
 
@@ -196,6 +197,10 @@ class const_and_copies
   void record_const_or_copy (tree, tree, tree);
 
  private:
+  /* Record a single const/copy pair that can be unwound.  This version
+     does not follow the value chain for the RHS.  */
+  void record_const_or_copy_raw (tree, tree, tree);
+
   vec<tree> m_stack;
   const_and_copies& operator= (const const_and_copies&);
   const_and_copies (class const_and_copies &);