[Bug c/14631] common subexpression elimilation error with sse2 instrinsic _mm_insert_epi16

[chbchb1130 at sina dot com]

------- Additional Comments From chbchb1130 at sina dot com  2004-03-18 13:37 -------
(In reply to comment #0)
> when gcc do cse with my sse2 program,it eliminate the RTL generate by 
> _mm_insert_epi16 mistakenly.

(In reply to comment #1)
> Created an attachment (id=5940)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5940&action=view)
> preprocessed testcase
> when I turn on the -O optimization swith,I get the wrong result:
> 65535	65535	65535	65535	65535	65535	65535	65535
> 0	0	0	0	0	0	0	0
> 65535	65535	65535	65535	65535	65535	65535	65535
> the correct result is :
> 65535	65535	65535	65535	65535	65535	65535	65535
> 0	65535	65535	65535	65535	65535	65535	65535
> 65535	65535	65535	65535	65535	65535	65535	65535
if I modify the pattern of sse2_pinsrw in i386.md :22089 from vector_merge to 
unspec, the bug is fixed.
initial version:
(define_insn "sse2_pinsrw"
  [(set (match_operand:V8HI 0 "register_operand" "=x")
        (vec_merge:V8HI (match_operand:V8HI 1 "register_operand" "0")
                        (vec_duplicate:V8HI
                         (truncate:HI
                           (match_operand:SI 2 "nonimmediate_operand" "rm")))
                        (match_operand:SI 3 "const_0_to_255_operand" "N")))]
  "TARGET_SSE2"
  "pinsrw\t{%3, %2, %0|%0, %2, %3}"
  [(set_attr "type" "ssecvt")
   (set_attr "mode" "TI")])
modified version:
(define_insn "sse2_pinsrw"
  [(set (match_operand:V8HI 0 "register_operand" "=x")
        (unspec:V8HI (match_operand:V8HI 1 "register_operand" "0")
                        (vec_duplicate:V8HI
                         (truncate:HI
                           (match_operand:SI 2 "nonimmediate_operand" "rm")))
                        (match_operand:SI 3 "const_0_to_255_operand" "N")))]
  "TARGET_SSE2"
  "pinsrw\t{%3, %2, %0|%0, %2, %3}"
  [(set_attr "type" "ssecvt")
   (set_attr "mode" "TI")])



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14631