On Fri, Nov 10, 2017 at 11:45:23AM -0600, Segher Boessenkool wrote:
> Hi Mike,
>
> On Wed, Nov 08, 2017 at 03:02:30PM -0500, Michael Meissner wrote:
> > > Should this somehow be joined with p9_xxbrd_<mode>? Or maybe you should
> > > generate that, instead.
> >
> > No, since p9_xxbrd_<mode> doesn't include DImode. We could add yet another
> > mode iterator to include DI + V2DI/V2DF modes, but that seems to be
> > overkill.
>
> Having separate DI and V2DI patterns for the same instruction isn't great
> either. If it is only this insn it is fine of course, but I suspect we'll
> get many more later. Well I guess we can solve it later ;-)
>
> > I simplified it to only change the one insn that would normally match the
> > register to register case to skip if ISA 3.0. I put a test on bswapdi2_reg
> > as
> > well.
>
> Thanks.
>
> >
> > > > @@ -2507,6 +2513,8 @@ (define_expand "bswapdi2"
> > > > emit_insn (gen_bswapdi2_load (dest, src));
> > > > else if (MEM_P (dest))
> > > > emit_insn (gen_bswapdi2_store (dest, src));
> > > > + else if (TARGET_P9_VECTOR)
> > > > + emit_insn (gen_bswapdi2_xxbrd (dest, src));
> > > > else
> > > > emit_insn (gen_bswapdi2_reg (dest, src));
> > > > DONE;
> > >
> > > Pity that you cannot easily do similar for HI and SI.
> >
> > Not really. Bswap64 generates 9 separate insns, while bswap32 and bswap16
> > only
> > generate 3 insns. So, having to add the move direct to/from the vector
> > registers would mean it would be slower than the normal case that is
> > currently
> > generated. But if the value happens to be in a VSX register, then we can
> > do it
> > in one instruction.
>
> I meant, have just two lines as above :-)
>
> > After a burn-in period, I plan to backport a reduced version of the patch
> > (XXBRD only) to gcc 7, unless you think it shouldn't go into gcc 7.
>
> Well, why do we want it on 7?
Advanced customers and the kernel team using pre-production power9 servers have
asked for it. Since GCC 8 likely won't be out for several months, I figured to
ask for it to go into GCC 7.
> > +(define_insn "bswapdi2_xxbrd"
> > + [(set (match_operand:DI 0 "gpc_reg_operand" "=wo")
> > + (bswap:DI (match_operand:DI 1 "gpc_reg_operand" "wo")))]
> > + "TARGET_POWERPC64 && TARGET_P9_VECTOR"
> > + "xxbrd %x0,%x1"
> > + [(set_attr "type" "vecperm")])
>
> This doesn't need TARGET_POWERPC64 I think.
>
> Please look at that. The patch is okay for trunk. Thanks!
I removed the test for POWERPC64. It isn't needed, but I don't have any way of
testing whether the resulting code is slower or faster. I'll attach the patch
of the changes I checked in.
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meiss...@linux.vnet.ibm.com, phone: +1 (978) 899-4797
Index: gcc/config/rs6000/rs6000.md
===================================================================
--- gcc/config/rs6000/rs6000.md (revision 254637)
+++ gcc/config/rs6000/rs6000.md (working copy)
@@ -2432,13 +2432,15 @@ (define_insn "bswap<mode>2_store"
[(set_attr "type" "store")])
(define_insn_and_split "bswaphi2_reg"
- [(set (match_operand:HI 0 "gpc_reg_operand" "=&r")
+ [(set (match_operand:HI 0 "gpc_reg_operand" "=&r,wo")
(bswap:HI
- (match_operand:HI 1 "gpc_reg_operand" "r")))
- (clobber (match_scratch:SI 2 "=&r"))]
+ (match_operand:HI 1 "gpc_reg_operand" "r,wo")))
+ (clobber (match_scratch:SI 2 "=&r,X"))]
""
- "#"
- "reload_completed"
+ "@
+ #
+ xxbrh %x0,%x1"
+ "reload_completed && int_reg_operand (operands[0], HImode)"
[(set (match_dup 3)
(and:SI (lshiftrt:SI (match_dup 4)
(const_int 8))
@@ -2454,18 +2456,20 @@ (define_insn_and_split "bswaphi2_reg"
operands[3] = simplify_gen_subreg (SImode, operands[0], HImode, 0);
operands[4] = simplify_gen_subreg (SImode, operands[1], HImode, 0);
}
- [(set_attr "length" "12")
- (set_attr "type" "*")])
+ [(set_attr "length" "12,4")
+ (set_attr "type" "*,vecperm")])
;; We are always BITS_BIG_ENDIAN, so the bit positions below in
;; zero_extract insns do not change for -mlittle.
(define_insn_and_split "bswapsi2_reg"
- [(set (match_operand:SI 0 "gpc_reg_operand" "=&r")
+ [(set (match_operand:SI 0 "gpc_reg_operand" "=&r,wo")
(bswap:SI
- (match_operand:SI 1 "gpc_reg_operand" "r")))]
+ (match_operand:SI 1 "gpc_reg_operand" "r,wo")))]
""
- "#"
- "reload_completed"
+ "@
+ #
+ xxbrw %x0,%x1"
+ "reload_completed && int_reg_operand (operands[0], SImode)"
[(set (match_dup 0) ; DABC
(rotate:SI (match_dup 1)
(const_int 24)))
@@ -2481,7 +2485,9 @@ (define_insn_and_split "bswapsi2_reg"
(const_int 255))
(and:SI (match_dup 0)
(const_int -256))))]
- "")
+ ""
+ [(set_attr "length" "12,4")
+ (set_attr "type" "*,vecperm")])
;; On systems with LDBRX/STDBRX generate the loads/stores directly, just like
;; we do for L{H,W}BRX and ST{H,W}BRX above. If not, we have to generate more
@@ -2507,11 +2513,19 @@ (define_expand "bswapdi2"
emit_insn (gen_bswapdi2_load (dest, src));
else if (MEM_P (dest))
emit_insn (gen_bswapdi2_store (dest, src));
+ else if (TARGET_P9_VECTOR)
+ emit_insn (gen_bswapdi2_xxbrd (dest, src));
else
emit_insn (gen_bswapdi2_reg (dest, src));
DONE;
}
+ if (TARGET_P9_VECTOR && !MEM_P (src) && !MEM_P (dest))
+ {
+ emit_insn (gen_bswapdi2_xxbrd (dest, src));
+ DONE;
+ }
+
if (!TARGET_POWERPC64)
{
/* 32-bit mode needs fewer scratch registers, but 32-bit addressing mode
@@ -2537,12 +2551,19 @@ (define_insn "bswapdi2_store"
"stdbrx %1,%y0"
[(set_attr "type" "store")])
+(define_insn "bswapdi2_xxbrd"
+ [(set (match_operand:DI 0 "gpc_reg_operand" "=wo")
+ (bswap:DI (match_operand:DI 1 "gpc_reg_operand" "wo")))]
+ "TARGET_P9_VECTOR"
+ "xxbrd %x0,%x1"
+ [(set_attr "type" "vecperm")])
+
(define_insn "bswapdi2_reg"
[(set (match_operand:DI 0 "gpc_reg_operand" "=&r")
(bswap:DI (match_operand:DI 1 "gpc_reg_operand" "r")))
(clobber (match_scratch:DI 2 "=&r"))
(clobber (match_scratch:DI 3 "=&r"))]
- "TARGET_POWERPC64 && TARGET_LDBRX"
+ "TARGET_POWERPC64 && TARGET_LDBRX && !TARGET_P9_VECTOR"
"#"
[(set_attr "length" "36")])
@@ -2691,7 +2712,7 @@ (define_split
(bswap:DI (match_operand:DI 1 "gpc_reg_operand" "")))
(clobber (match_operand:DI 2 "gpc_reg_operand" ""))
(clobber (match_operand:DI 3 "gpc_reg_operand" ""))]
- "TARGET_POWERPC64 && reload_completed"
+ "TARGET_POWERPC64 && !TARGET_P9_VECTOR && reload_completed"
[(const_int 0)]
"
{
Index: gcc/testsuite/gcc.target/powerpc/p9-xxbr-3.c
===================================================================
--- gcc/testsuite/gcc.target/powerpc/p9-xxbr-3.c (revision 0)
+++ gcc/testsuite/gcc.target/powerpc/p9-xxbr-3.c (revision 0)
@@ -0,0 +1,99 @@
+/* { dg-do compile { target { powerpc*-*-* && lp64 } } } */
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-options "-mpower9-vector -O2" } */
+
+/* Verify that the XXBR{H,W} instructions are generated if the value is
+ forced to be in a vector register, and XXBRD is generated all of the
+ time for register bswap64's. */
+
+unsigned short
+do_bswap16_mem (unsigned short *p)
+{
+ return __builtin_bswap16 (*p); /* LHBRX. */
+}
+
+unsigned short
+do_bswap16_reg (unsigned short a)
+{
+ return __builtin_bswap16 (a); /* gpr sequences. */
+}
+
+void
+do_bswap16_store (unsigned short *p, unsigned short a)
+{
+ *p = __builtin_bswap16 (a); /* STHBRX. */
+}
+
+unsigned short
+do_bswap16_vect (unsigned short a)
+{
+ __asm__ (" # %x0" : "+v" (a));
+ return __builtin_bswap16 (a); /* XXBRW. */
+}
+
+unsigned int
+do_bswap32_mem (unsigned int *p)
+{
+ return __builtin_bswap32 (*p); /* LWBRX. */
+}
+
+unsigned int
+do_bswap32_reg (unsigned int a)
+{
+ return __builtin_bswap32 (a); /* gpr sequences. */
+}
+
+void
+do_bswap32_store (unsigned int *p, unsigned int a)
+{
+ *p = __builtin_bswap32 (a); /* STWBRX. */
+}
+
+unsigned int
+do_bswap32_vect (unsigned int a)
+{
+ __asm__ (" # %x0" : "+v" (a));
+ return __builtin_bswap32 (a); /* XXBRW. */
+}
+
+unsigned long
+do_bswap64_mem (unsigned long *p)
+{
+ return __builtin_bswap64 (*p); /* LDBRX. */
+}
+
+unsigned long
+do_bswap64_reg (unsigned long a)
+{
+ return __builtin_bswap64 (a); /* gpr sequences. */
+}
+
+void
+do_bswap64_store (unsigned long *p, unsigned int a)
+{
+ *p = __builtin_bswap64 (a); /* STDBRX. */
+}
+
+double
+do_bswap64_double (unsigned long a)
+{
+ return (double) __builtin_bswap64 (a); /* XXBRD. */
+}
+
+unsigned long
+do_bswap64_vect (unsigned long a)
+{
+ __asm__ (" # %x0" : "+v" (a)); /* XXBRD. */
+ return __builtin_bswap64 (a);
+}
+
+/* Make sure XXBR{H,W,D} is not generated by default. */
+/* { dg-final { scan-assembler-times "xxbrd" 3 } } */
+/* { dg-final { scan-assembler-times "xxbrh" 1 } } */
+/* { dg-final { scan-assembler-times "xxbrw" 1 } } */
+/* { dg-final { scan-assembler-times "ldbrx" 1 } } */
+/* { dg-final { scan-assembler-times "lhbrx" 1 } } */
+/* { dg-final { scan-assembler-times "lwbrx" 1 } } */
+/* { dg-final { scan-assembler-times "stdbrx" 1 } } */
+/* { dg-final { scan-assembler-times "sthbrx" 1 } } */
+/* { dg-final { scan-assembler-times "stwbrx" 1 } } */
