r210340 - [PPC64LE] Implement little-endian semantics for vec_pack family
Bill Schmidt
wschmidt at linux.vnet.ibm.com
Fri Jun 6 09:24:52 PDT 2014
On Fri, 2014-06-06 at 11:07 -0500, Hal Finkel wrote:
> ----- Original Message -----
> > From: "Bill Schmidt" <wschmidt at linux.vnet.ibm.com>
> > To: cfe-commits at cs.uiuc.edu
> > Sent: Friday, June 6, 2014 10:10:47 AM
> > Subject: r210340 - [PPC64LE] Implement little-endian semantics for vec_pack family
> >
> > Author: wschmidt
> > Date: Fri Jun 6 10:10:47 2014
> > New Revision: 210340
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=210340&view=rev
> > Log:
> > [PPC64LE] Implement little-endian semantics for vec_pack family
> >
> > The PowerPC vector-pack instructions are defined architecturally with
> > a big-endian bias, in that the vector element numbering is assumed to
> > be "left to right" regardless of whether the processor is in
> > big-endian or little-endian mode. This definition is unnatural for
> > little-endian code generation.
> >
> > To facilitate ease of porting, the vec_pack and related interfaces
> > are
> > designed to use natural element ordering, so that elements are
> > numbered according to little-endian design principles when code is
> > generated for a little-endian target. The vec_pack calls are
> > implemented as calls to vec_perm, specifying selection of the
> > odd-numbered vector elements. For little endian, this means the
> > odd-numbered elements counting from the right end of the register.
> > Since the underlying instructions count from the left end, we must
> > instead select the even-numbered vector elements for little endian to
> > achieve the desired semantics.
> >
> > The correctness of this code is tested by the new pack.c test added
> > in
> > a previous patch. I plan to later make the existing ppc32 Altivec
> > compile-time tests work for ppc64 and ppc64le as well.
>
> I don't understand this...
>
> test/CodeGen/builtins-ppc-altivec.c seems to be the relevant place to test this, and this test works fine on ppc64 (if you change the current triple from powerpc-unknown-unknown to powerpc64-unknown-unknown it still passes). Please do this and add tests for these changes there.
Yes, these are the tests that I'm planning to fix as well. And the test
indeed passes with the powerpc64-unknown-gnu triple. However, there are
many variants in that test that fail with the powerpc64le-unknown-gnu
triple because the LE support is not yet in place, so I was putting off
implementing all the changes in that test until the various fixes to
altivec.h are in. The alternative is to implement it piecemeal and
XFAIL the test for powerpc64le-unknown-gnu until all the pieces are in
place. Is that preferable?
Thanks,
Bill
>
> Thanks again,
> Hal
>
> >
> > Modified:
> > cfe/trunk/lib/Headers/altivec.h
> >
> > Modified: cfe/trunk/lib/Headers/altivec.h
> > URL:
> > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/altivec.h?rev=210340&r1=210339&r2=210340&view=diff
> > ==============================================================================
> > --- cfe/trunk/lib/Headers/altivec.h (original)
> > +++ cfe/trunk/lib/Headers/altivec.h Fri Jun 6 10:10:47 2014
> > @@ -4117,52 +4117,91 @@ vec_vor(vector float __a, vector bool in
> >
> > /* vec_pack */
> >
> > +/* The various vector pack instructions have a big-endian bias, so
> > for
> > + little endian we must handle reversed element numbering. */
> > +
> > static vector signed char __ATTRS_o_ai
> > vec_pack(vector signed short __a, vector signed short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector signed char)vec_perm(__a, __b, (vector unsigned
> > char)
> > + (0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E,
> > + 0x10, 0x12, 0x14, 0x16, 0x18, 0x1A, 0x1C, 0x1E));
> > +#else
> > return (vector signed char)vec_perm(__a, __b, (vector unsigned
> > char)
> > (0x01, 0x03, 0x05, 0x07, 0x09, 0x0B, 0x0D, 0x0F,
> > 0x11, 0x13, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F));
> > +#endif
> > }
> >
> > static vector unsigned char __ATTRS_o_ai
> > vec_pack(vector unsigned short __a, vector unsigned short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector unsigned char)vec_perm(__a, __b, (vector unsigned
> > char)
> > + (0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E,
> > + 0x10, 0x12, 0x14, 0x16, 0x18, 0x1A, 0x1C, 0x1E));
> > +#else
> > return (vector unsigned char)vec_perm(__a, __b, (vector unsigned
> > char)
> > (0x01, 0x03, 0x05, 0x07, 0x09, 0x0B, 0x0D, 0x0F,
> > 0x11, 0x13, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F));
> > +#endif
> > }
> >
> > static vector bool char __ATTRS_o_ai
> > vec_pack(vector bool short __a, vector bool short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector bool char)vec_perm(__a, __b, (vector unsigned char)
> > + (0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E,
> > + 0x10, 0x12, 0x14, 0x16, 0x18, 0x1A, 0x1C, 0x1E));
> > +#else
> > return (vector bool char)vec_perm(__a, __b, (vector unsigned char)
> > (0x01, 0x03, 0x05, 0x07, 0x09, 0x0B, 0x0D, 0x0F,
> > 0x11, 0x13, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F));
> > +#endif
> > }
> >
> > static vector short __ATTRS_o_ai
> > vec_pack(vector int __a, vector int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector short)vec_perm(__a, __b, (vector unsigned char)
> > + (0x00, 0x01, 0x04, 0x05, 0x08, 0x09, 0x0C, 0x0D,
> > + 0x10, 0x11, 0x14, 0x15, 0x18, 0x19, 0x1C, 0x1D));
> > +#else
> > return (vector short)vec_perm(__a, __b, (vector unsigned char)
> > (0x02, 0x03, 0x06, 0x07, 0x0A, 0x0B, 0x0E, 0x0F,
> > 0x12, 0x13, 0x16, 0x17, 0x1A, 0x1B, 0x1E, 0x1F));
> > +#endif
> > }
> >
> > static vector unsigned short __ATTRS_o_ai
> > vec_pack(vector unsigned int __a, vector unsigned int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector unsigned short)vec_perm(__a, __b, (vector unsigned
> > char)
> > + (0x00, 0x01, 0x04, 0x05, 0x08, 0x09, 0x0C, 0x0D,
> > + 0x10, 0x11, 0x14, 0x15, 0x18, 0x19, 0x1C, 0x1D));
> > +#else
> > return (vector unsigned short)vec_perm(__a, __b, (vector unsigned
> > char)
> > (0x02, 0x03, 0x06, 0x07, 0x0A, 0x0B, 0x0E, 0x0F,
> > 0x12, 0x13, 0x16, 0x17, 0x1A, 0x1B, 0x1E, 0x1F));
> > +#endif
> > }
> >
> > static vector bool short __ATTRS_o_ai
> > vec_pack(vector bool int __a, vector bool int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector unsigned short)vec_perm(__a, __b, (vector unsigned
> > char)
> > + (0x00, 0x01, 0x04, 0x05, 0x08, 0x09, 0x0C, 0x0D,
> > + 0x10, 0x11, 0x14, 0x15, 0x18, 0x19, 0x1C, 0x1D));
> > +#else
> > return (vector bool short)vec_perm(__a, __b, (vector unsigned
> > char)
> > (0x02, 0x03, 0x06, 0x07, 0x0A, 0x0B, 0x0E, 0x0F,
> > 0x12, 0x13, 0x16, 0x17, 0x1A, 0x1B, 0x1E, 0x1F));
> > +#endif
> > }
> >
> > /* vec_vpkuhum */
> > @@ -4172,25 +4211,43 @@ vec_pack(vector bool int __a, vector boo
> > static vector signed char __ATTRS_o_ai
> > vec_vpkuhum(vector signed short __a, vector signed short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector signed char)vec_perm(__a, __b, (vector unsigned
> > char)
> > + (0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E,
> > + 0x10, 0x12, 0x14, 0x16, 0x18, 0x1A, 0x1C, 0x1E));
> > +#else
> > return (vector signed char)vec_perm(__a, __b, (vector unsigned
> > char)
> > (0x01, 0x03, 0x05, 0x07, 0x09, 0x0B, 0x0D, 0x0F,
> > 0x11, 0x13, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F));
> > +#endif
> > }
> >
> > static vector unsigned char __ATTRS_o_ai
> > vec_vpkuhum(vector unsigned short __a, vector unsigned short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector unsigned char)vec_perm(__a, __b, (vector unsigned
> > char)
> > + (0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E,
> > + 0x10, 0x12, 0x14, 0x16, 0x18, 0x1A, 0x1C, 0x1E));
> > +#else
> > return (vector unsigned char)vec_perm(__a, __b, (vector unsigned
> > char)
> > (0x01, 0x03, 0x05, 0x07, 0x09, 0x0B, 0x0D, 0x0F,
> > 0x11, 0x13, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F));
> > +#endif
> > }
> >
> > static vector bool char __ATTRS_o_ai
> > vec_vpkuhum(vector bool short __a, vector bool short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector bool char)vec_perm(__a, __b, (vector unsigned char)
> > + (0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E,
> > + 0x10, 0x12, 0x14, 0x16, 0x18, 0x1A, 0x1C, 0x1E));
> > +#else
> > return (vector bool char)vec_perm(__a, __b, (vector unsigned char)
> > (0x01, 0x03, 0x05, 0x07, 0x09, 0x0B, 0x0D, 0x0F,
> > 0x11, 0x13, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F));
> > +#endif
> > }
> >
> > /* vec_vpkuwum */
> > @@ -4200,25 +4257,43 @@ vec_vpkuhum(vector bool short __a, vecto
> > static vector short __ATTRS_o_ai
> > vec_vpkuwum(vector int __a, vector int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector short)vec_perm(__a, __b, (vector unsigned char)
> > + (0x00, 0x01, 0x04, 0x05, 0x08, 0x09, 0x0C, 0x0D,
> > + 0x10, 0x11, 0x14, 0x15, 0x18, 0x19, 0x1C, 0x1D));
> > +#else
> > return (vector short)vec_perm(__a, __b, (vector unsigned char)
> > (0x02, 0x03, 0x06, 0x07, 0x0A, 0x0B, 0x0E, 0x0F,
> > 0x12, 0x13, 0x16, 0x17, 0x1A, 0x1B, 0x1E, 0x1F));
> > +#endif
> > }
> >
> > static vector unsigned short __ATTRS_o_ai
> > vec_vpkuwum(vector unsigned int __a, vector unsigned int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector unsigned short)vec_perm(__a, __b, (vector unsigned
> > char)
> > + (0x00, 0x01, 0x04, 0x05, 0x08, 0x09, 0x0C, 0x0D,
> > + 0x10, 0x11, 0x14, 0x15, 0x18, 0x19, 0x1C, 0x1D));
> > +#else
> > return (vector unsigned short)vec_perm(__a, __b, (vector unsigned
> > char)
> > (0x02, 0x03, 0x06, 0x07, 0x0A, 0x0B, 0x0E, 0x0F,
> > 0x12, 0x13, 0x16, 0x17, 0x1A, 0x1B, 0x1E, 0x1F));
> > +#endif
> > }
> >
> > static vector bool short __ATTRS_o_ai
> > vec_vpkuwum(vector bool int __a, vector bool int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector bool short)vec_perm(__a, __b, (vector unsigned
> > char)
> > + (0x00, 0x01, 0x04, 0x05, 0x08, 0x09, 0x0C, 0x0D,
> > + 0x10, 0x11, 0x14, 0x15, 0x18, 0x19, 0x1C, 0x1D));
> > +#else
> > return (vector bool short)vec_perm(__a, __b, (vector unsigned
> > char)
> > (0x02, 0x03, 0x06, 0x07, 0x0A, 0x0B, 0x0E, 0x0F,
> > 0x12, 0x13, 0x16, 0x17, 0x1A, 0x1B, 0x1E, 0x1F));
> > +#endif
> > }
> >
> > /* vec_packpx */
> > @@ -4226,7 +4301,11 @@ vec_vpkuwum(vector bool int __a, vector
> > static vector pixel __attribute__((__always_inline__))
> > vec_packpx(vector unsigned int __a, vector unsigned int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector pixel)__builtin_altivec_vpkpx(__b, __a);
> > +#else
> > return (vector pixel)__builtin_altivec_vpkpx(__a, __b);
> > +#endif
> > }
> >
> > /* vec_vpkpx */
> > @@ -4234,7 +4313,11 @@ vec_packpx(vector unsigned int __a, vect
> > static vector pixel __attribute__((__always_inline__))
> > vec_vpkpx(vector unsigned int __a, vector unsigned int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return (vector pixel)__builtin_altivec_vpkpx(__b, __a);
> > +#else
> > return (vector pixel)__builtin_altivec_vpkpx(__a, __b);
> > +#endif
> > }
> >
> > /* vec_packs */
> > @@ -4242,25 +4325,41 @@ vec_vpkpx(vector unsigned int __a, vecto
> > static vector signed char __ATTRS_o_ai
> > vec_packs(vector short __a, vector short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkshss(__b, __a);
> > +#else
> > return __builtin_altivec_vpkshss(__a, __b);
> > +#endif
> > }
> >
> > static vector unsigned char __ATTRS_o_ai
> > vec_packs(vector unsigned short __a, vector unsigned short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkuhus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkuhus(__a, __b);
> > +#endif
> > }
> >
> > static vector signed short __ATTRS_o_ai
> > vec_packs(vector int __a, vector int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkswss(__b, __a);
> > +#else
> > return __builtin_altivec_vpkswss(__a, __b);
> > +#endif
> > }
> >
> > static vector unsigned short __ATTRS_o_ai
> > vec_packs(vector unsigned int __a, vector unsigned int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkuwus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkuwus(__a, __b);
> > +#endif
> > }
> >
> > /* vec_vpkshss */
> > @@ -4268,7 +4367,11 @@ vec_packs(vector unsigned int __a, vecto
> > static vector signed char __attribute__((__always_inline__))
> > vec_vpkshss(vector short __a, vector short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkshss(__b, __a);
> > +#else
> > return __builtin_altivec_vpkshss(__a, __b);
> > +#endif
> > }
> >
> > /* vec_vpkuhus */
> > @@ -4276,7 +4379,11 @@ vec_vpkshss(vector short __a, vector sho
> > static vector unsigned char __attribute__((__always_inline__))
> > vec_vpkuhus(vector unsigned short __a, vector unsigned short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkuhus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkuhus(__a, __b);
> > +#endif
> > }
> >
> > /* vec_vpkswss */
> > @@ -4284,7 +4391,11 @@ vec_vpkuhus(vector unsigned short __a, v
> > static vector signed short __attribute__((__always_inline__))
> > vec_vpkswss(vector int __a, vector int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkswss(__b, __a);
> > +#else
> > return __builtin_altivec_vpkswss(__a, __b);
> > +#endif
> > }
> >
> > /* vec_vpkuwus */
> > @@ -4292,7 +4403,11 @@ vec_vpkswss(vector int __a, vector int _
> > static vector unsigned short __attribute__((__always_inline__))
> > vec_vpkuwus(vector unsigned int __a, vector unsigned int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkuwus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkuwus(__a, __b);
> > +#endif
> > }
> >
> > /* vec_packsu */
> > @@ -4300,25 +4415,41 @@ vec_vpkuwus(vector unsigned int __a, vec
> > static vector unsigned char __ATTRS_o_ai
> > vec_packsu(vector short __a, vector short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkshus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkshus(__a, __b);
> > +#endif
> > }
> >
> > static vector unsigned char __ATTRS_o_ai
> > vec_packsu(vector unsigned short __a, vector unsigned short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkuhus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkuhus(__a, __b);
> > +#endif
> > }
> >
> > static vector unsigned short __ATTRS_o_ai
> > vec_packsu(vector int __a, vector int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkswus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkswus(__a, __b);
> > +#endif
> > }
> >
> > static vector unsigned short __ATTRS_o_ai
> > vec_packsu(vector unsigned int __a, vector unsigned int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkuwus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkuwus(__a, __b);
> > +#endif
> > }
> >
> > /* vec_vpkshus */
> > @@ -4326,13 +4457,21 @@ vec_packsu(vector unsigned int __a, vect
> > static vector unsigned char __ATTRS_o_ai
> > vec_vpkshus(vector short __a, vector short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkshus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkshus(__a, __b);
> > +#endif
> > }
> >
> > static vector unsigned char __ATTRS_o_ai
> > vec_vpkshus(vector unsigned short __a, vector unsigned short __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkuhus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkuhus(__a, __b);
> > +#endif
> > }
> >
> > /* vec_vpkswus */
> > @@ -4340,13 +4479,21 @@ vec_vpkshus(vector unsigned short __a, v
> > static vector unsigned short __ATTRS_o_ai
> > vec_vpkswus(vector int __a, vector int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkswus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkswus(__a, __b);
> > +#endif
> > }
> >
> > static vector unsigned short __ATTRS_o_ai
> > vec_vpkswus(vector unsigned int __a, vector unsigned int __b)
> > {
> > +#ifdef __LITTLE_ENDIAN__
> > + return __builtin_altivec_vpkuwus(__b, __a);
> > +#else
> > return __builtin_altivec_vpkuwus(__a, __b);
> > +#endif
> > }
> >
> > /* vec_perm */
> >
> >
> > _______________________________________________
> > cfe-commits mailing list
> > cfe-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
> >
>
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