PR tree-optimization/80934 - bzero should be assumed not to escape pointer argument

PR tree-optimization/80934 - bzero should be assumed not to escape pointer argument
PR tree-optimization/80933 - redundant bzero/bcopy calls not eliminated

gcc/ChangeLog:

	PR tree-optimization/80933
	PR tree-optimization/80934
	* builtins.c (fold_builtin_3): Do not handle bcmp here.
	* gimple-fold.c (gimple_fold_builtin_bcmp): New function.
	(gimple_fold_builtin_bcopy, gimple_fold_builtin_bzero): Likewise.
	(gimple_fold_builtin): Call them.

gcc/testsuite/ChangeLog:

	PR tree-optimization/80933
	PR tree-optimization/80934
	* gcc.dg/fold-bcopy.c: New test.
	* gcc.dg/tree-ssa/ssa-dse-30.c: Likewise..
	* gcc.dg/tree-ssa/alias-36.c: Likewise.
	* gcc/testsuite/gcc.dg/pr79214.c: Adjust.
	* gcc.dg/tree-prof/val-prof-7.c: Likewise.
	* gcc.dg/Wsizeof-pointer-memaccess1.c: Likewise.
	* gcc.dg/builtins-nonnull.c: Likewise.

From-SVN: r249278

1 files changed, 83 insertions, 5 deletions

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 0f8e326..a00c2c8 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -1077,6 +1077,83 @@ done:
   return true;
 }
 
+/* Transform a call to built-in bcmp(a, b, len) at *GSI into one
+   to built-in memcmp (a, b, len).  */
+
+static bool
+gimple_fold_builtin_bcmp (gimple_stmt_iterator *gsi)
+{
+  tree fn = builtin_decl_implicit (BUILT_IN_MEMCMP);
+
+  if (!fn)
+    return false;
+
+  /* Transform bcmp (a, b, len) into memcmp (a, b, len).  */
+
+  gimple *stmt = gsi_stmt (*gsi);
+  tree a = gimple_call_arg (stmt, 0);
+  tree b = gimple_call_arg (stmt, 1);
+  tree len = gimple_call_arg (stmt, 2);
+
+  gimple *repl = gimple_build_call (fn, 3, a, b, len);
+  replace_call_with_call_and_fold (gsi, repl);
+
+  return true;
+}
+
+/* Transform a call to built-in bcopy (src, dest, len) at *GSI into one
+   to built-in memmove (dest, src, len).  */
+
+static bool
+gimple_fold_builtin_bcopy (gimple_stmt_iterator *gsi)
+{
+  tree fn = builtin_decl_implicit (BUILT_IN_MEMMOVE);
+
+  if (!fn)
+    return false;
+
+  /* bcopy has been removed from POSIX in Issue 7 but Issue 6 specifies
+     it's quivalent to memmove (not memcpy).  Transform bcopy (src, dest,
+     len) into memmove (dest, src, len).  */
+
+  gimple *stmt = gsi_stmt (*gsi);
+  tree src = gimple_call_arg (stmt, 0);
+  tree dest = gimple_call_arg (stmt, 1);
+  tree len = gimple_call_arg (stmt, 2);
+
+  gimple *repl = gimple_build_call (fn, 3, dest, src, len);
+  gimple_call_set_fntype (as_a <gcall *> (stmt), TREE_TYPE (fn));
+  replace_call_with_call_and_fold (gsi, repl);
+
+  return true;
+}
+
+/* Transform a call to built-in bzero (dest, len) at *GSI into one
+   to built-in memset (dest, 0, len).  */
+
+static bool
+gimple_fold_builtin_bzero (gimple_stmt_iterator *gsi)
+{
+  tree fn = builtin_decl_implicit (BUILT_IN_MEMSET);
+
+  if (!fn)
+    return false;
+
+  /* Transform bzero (dest, len) into memset (dest, 0, len).  */
+
+  gimple *stmt = gsi_stmt (*gsi);
+  tree dest = gimple_call_arg (stmt, 0);
+  tree len = gimple_call_arg (stmt, 1);
+
+  gimple_seq seq = NULL;
+  gimple *repl = gimple_build_call (fn, 3, dest, integer_zero_node, len);
+  gimple_seq_add_stmt_without_update (&seq, repl);
+  gsi_replace_with_seq_vops (gsi, seq);
+  fold_stmt (gsi);
+
+  return true;
+}
+
 /* Fold function call to builtin memset or bzero at *GSI setting the
    memory of size LEN to VAL.  Return whether a simplification was made.  */
 
@@ -3288,16 +3365,17 @@ gimple_fold_builtin (gimple_stmt_iterator *gsi)
   enum built_in_function fcode = DECL_FUNCTION_CODE (callee);
   switch (fcode)
     {
+    case BUILT_IN_BCMP:
+      return gimple_fold_builtin_bcmp (gsi);
+    case BUILT_IN_BCOPY:
+      return gimple_fold_builtin_bcopy (gsi);
     case BUILT_IN_BZERO:
-      return gimple_fold_builtin_memset (gsi, integer_zero_node,
-					 gimple_call_arg (stmt, 1));
+      return gimple_fold_builtin_bzero (gsi);
+
     case BUILT_IN_MEMSET:
       return gimple_fold_builtin_memset (gsi,
 					 gimple_call_arg (stmt, 1),
 					 gimple_call_arg (stmt, 2));
-    case BUILT_IN_BCOPY:
-      return gimple_fold_builtin_memory_op (gsi, gimple_call_arg (stmt, 1),
-					    gimple_call_arg (stmt, 0), 3);
     case BUILT_IN_MEMCPY:
       return gimple_fold_builtin_memory_op (gsi, gimple_call_arg (stmt, 0),
 					    gimple_call_arg (stmt, 1), 0);