------- Additional Comments From uros at kss-loka dot si 2005-06-22 10:14
-------
Just for fun, I have compiled the testcase with MMX/x87 mode switching patch
included, to check MMX vector extensions. This little patch is needed to enable
MMX vector extensions (only MMX vector add expander is shown):
diff -upr /export/home/uros/gcc-back/gcc/config/i386/i386.h i386/i386.h
--- /export/home/uros/gcc-back/gcc/config/i386/i386.h 2005-06-08
07:05:22.000000000 +0200
+++ i386/i386.h 2005-06-22 10:41:31.000000000 +0200
@@ -843,7 +845,8 @@ do {
\
/* ??? No autovectorization into MMX or 3DNOW until we can reliably
place emms and femms instructions. */
-#define UNITS_PER_SIMD_WORD (TARGET_SSE ? 16 : UNITS_PER_WORD)
+#define UNITS_PER_SIMD_WORD \
+ (TARGET_SSE ? 16 : TARGET_MMX ? 8 : UNITS_PER_WORD)
#define VALID_FP_MODE_P(MODE) \
((MODE) == SFmode || (MODE) == DFmode || (MODE) == XFmode \
diff -upr /export/home/uros/gcc-back/gcc/config/i386/mmx.md i386/mmx.md
--- /export/home/uros/gcc-back/gcc/config/i386/mmx.md 2005-04-20
21:56:15.000000000 +0200
+++ i386/mmx.md 2005-06-22 11:00:35.000000000 +0200
@@ -553,6 +553,13 @@
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(define_expand "add<mode>3"
+ [(set (match_operand:MMXMODEI 0 "register_operand" "")
+ (plus:MMXMODEI (match_operand:MMXMODEI 1 "nonimmediate_operand" "")
+ (match_operand:MMXMODEI 2 "nonimmediate_operand" "")))]
+ "TARGET_MMX"
+ "ix86_fixup_binary_operands_no_copy (PLUS, <MODE>mode, operands);")
+
(define_insn "mmx_add<mode>3"
[(set (match_operand:MMXMODEI 0 "register_operand" "=y")
(plus:MMXMODEI
After that, the testcase from description is compiled to (with -fomit-frame-
pointer):
test:
movq w, %mm0
paddw %mm0, %mm0
movq %mm0, w
movq %mm0, dw
emms
ret
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |uros at kss-loka dot si
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14552
