gcc/

	PR rtl-optimization/33927
	* Makefile.in (dse.o): Depend on $(TM_P_H).
	* expr.h (extract_low_bits): Declare.
	* expmed.c (extract_low_bits): New function.
	* rtlhooks.c (gen_lowpart_general): Generalize SUBREG handling.
	* dse.c: Include tm_p.h.
	(find_shift_sequence): Remove the read_reg argument and return the
	read value.  Emit the instructions instead of returning them.
	Iterate on new_mode rather than calculating it each time.
	Check MODES_TIEABLE_P.  Use simplify_gen_subreg to convert the
	source to NEW_MODE and extract_low_bits to convert the shifted
	value to READ_MODE.
	(replace_read): Allow the load and store to have different mode
	classes.  Use extract_low_bits when SHIFT == 0.  Create the shift
	or extraction instructions before trying the replacement.  Update
	dump-file code accordingly, avoiding use of REGNO (store_info->rhs).

gcc/testsuite/
	* gcc.target/mips/dse-1.c: Add checks for zeros.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@133452 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 1 insertions, 0 deletions

diff --git a/gcc/expr.h b/gcc/expr.h
index 8cc5ae3ff80..e3b2471393a 100644
--- a/gcc/expr.h
+++ b/gcc/expr.h
@@ -744,6 +744,7 @@ extern void store_bit_field (rtx, unsigned HOST_WIDE_INT,
 extern rtx extract_bit_field (rtx, unsigned HOST_WIDE_INT,
 			      unsigned HOST_WIDE_INT, int, rtx,
 			      enum machine_mode, enum machine_mode);
+extern rtx extract_low_bits (enum machine_mode, enum machine_mode, rtx);
 extern rtx expand_mult (enum machine_mode, rtx, rtx, rtx, int);
 extern rtx expand_mult_highpart_adjust (enum machine_mode, rtx, rtx, rtx, rtx, int);