* expr.h (store_by_pieces): Add prototype.

	(can_store_by_pieces): Likewise.
	* expr.c (struct store_by_pieces): Renamed from clear_by_pieces.
	(can_store_by_pieces): New.
	(store_by_pieces): New.
	(clear_by_pieces): New.
	(clear_by_pieces_1): New.
	(store_by_pieces_1): Renamed from clear_by_pieces, handle storing
	arbitrary compiler generated constants into memory block.
	(store_by_pieces_2): Renamed from clear_by_pieces_1, likewise.
	* builtins.c (c_readstr): New.
	(builtin_memcpy_read_str): New.
	(expand_builtin_memcpy): If src is string constant and
	emit_block_move would move it by pieces, compute integer constants
	from the string and store it into memory block instead.
	(builtin_strncpy_read_str): New.
	(expand_builtin_strncpy): If N is not constant zero and c_strlen does
	not return INTEGER_CST, don't optimize.
	If N is larger than strlen(src) + 1, try to copy the string
	including padding with store_by_pieces.
	(expand_builtin_strcmp): If both arguments have side effects, don't
	optimize.
	(expand_builtin_fputs): If STR has side effects, don't optimize.

	* gcc.c-torture/execute/string-opt-5.c: Add some strcmp and strncpy
	tests.
	* gcc.c-torture/execute/string-opt-6.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@37851 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 19 insertions, 0 deletions

diff --git a/gcc/expr.h b/gcc/expr.h
index 8cb28361038..74af2d9957f 100644
--- a/gcc/expr.h
+++ b/gcc/expr.h
@@ -1010,6 +1010,25 @@ extern void use_group_regs PARAMS ((rtx *, rtx));
    alignment.  */
 extern rtx clear_storage PARAMS ((rtx, rtx, unsigned int));
 
+/* Return non-zero if it is desirable to store LEN bytes generated by
+   CONSTFUN with several move instructions by store_by_pieces
+   function.  CONSTFUNDATA is a pointer which will be passed as argument
+   in every CONSTFUN call.
+   ALIGN is maximum alignment we can assume.  */
+extern int can_store_by_pieces PARAMS ((unsigned HOST_WIDE_INT,
+					rtx (*) (PTR, HOST_WIDE_INT,
+						 enum machine_mode),
+					PTR, unsigned int));
+
+/* Generate several move instructions to store LEN bytes generated by
+   CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
+   pointer which will be passed as argument in every CONSTFUN call.
+   ALIGN is maximum alignment we can assume.  */
+extern void store_by_pieces PARAMS ((rtx, unsigned HOST_WIDE_INT,
+				     rtx (*) (PTR, HOST_WIDE_INT,
+					      enum machine_mode),
+				     PTR, unsigned int));
+
 /* Emit insns to set X from Y.  */
 extern rtx emit_move_insn PARAMS ((rtx, rtx));