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> -----Original Message----- > From: Tamar Christina > Sent: Monday, October 31, 2022 11:35 AM > To: Tamar Christina <tamar.christ...@arm.com>; gcc-patches@gcc.gnu.org > Cc: nd <n...@arm.com>; Richard Earnshaw <richard.earns...@arm.com>; > Marcus Shawcroft <marcus.shawcr...@arm.com>; Kyrylo Tkachov > <kyrylo.tkac...@arm.com>; Richard Sandiford > <richard.sandif...@arm.com> > Subject: RE: [PATCH 3/4]AArch64 Add SVE2 implementation for pow2 > bitmask division > > Ping > > > -----Original Message----- > > From: Tamar Christina <tamar.christ...@arm.com> > > Sent: Friday, September 23, 2022 10:34 AM > > To: gcc-patches@gcc.gnu.org > > Cc: nd <n...@arm.com>; Richard Earnshaw <richard.earns...@arm.com>; > > Marcus Shawcroft <marcus.shawcr...@arm.com>; Kyrylo Tkachov > > <kyrylo.tkac...@arm.com>; Richard Sandiford > > <richard.sandif...@arm.com> > > Subject: [PATCH 3/4]AArch64 Add SVE2 implementation for pow2 bitmask > > division > > > > Hi All, > > > > In plenty of image and video processing code it's common to modify > > pixel values by a widening operation and then scale them back into > > range by dividing by 255. > > > > This patch adds an named function to allow us to emit an optimized > > sequence when doing an unsigned division that is equivalent to: > > > > x = y / (2 ^ (bitsize (y)/2)-1) > > > > For SVE2 this means we generate for: > > > > void draw_bitmap1(uint8_t* restrict pixel, uint8_t level, int n) { > > for (int i = 0; i < (n & -16); i+=1) > > pixel[i] = (pixel[i] * level) / 0xff; } > > > > the following: > > > > mov z3.b, #1 > > .L3: > > ld1b z0.h, p0/z, [x0, x3] > > mul z0.h, p1/m, z0.h, z2.h > > addhnb z1.b, z0.h, z3.h > > addhnb z0.b, z0.h, z1.h > > st1b z0.h, p0, [x0, x3] > > inch x3 > > whilelo p0.h, w3, w2 > > b.any .L3 > > > > instead of: > > > > .L3: > > ld1b z0.h, p1/z, [x0, x3] > > mul z0.h, p0/m, z0.h, z1.h > > umulh z0.h, p0/m, z0.h, z2.h > > lsr z0.h, z0.h, #7 > > st1b z0.h, p1, [x0, x3] > > inch x3 > > whilelo p1.h, w3, w2 > > b.any .L3 > > > > Which results in significantly faster code. > > > > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues. > > > > Ok for master? > > > > Thanks, > > Tamar > > > > gcc/ChangeLog: > > > > * config/aarch64/aarch64-sve2.md > > (@aarch64_bitmask_udiv<mode>3): New. > > > > gcc/testsuite/ChangeLog: > > > > * gcc.target/aarch64/sve2/div-by-bitmask_1.c: New test. > > > > --- inline copy of patch -- > > diff --git a/gcc/config/aarch64/aarch64-sve2.md > > b/gcc/config/aarch64/aarch64-sve2.md > > index > > > f138f4be4bcf74c1a4a6d5847ed831435246737f..4d097f7c405cc68a1d6cda5c234 > > a1023a6eba0d1 100644 > > --- a/gcc/config/aarch64/aarch64-sve2.md > > +++ b/gcc/config/aarch64/aarch64-sve2.md > > @@ -71,6 +71,7 @@ > > ;; ---- [INT] Reciprocal approximation ;; ---- [INT<-FP] Base-2 > > logarithm ;; ---- [INT] Polynomial multiplication > > +;; ---- [INT] Misc optab implementations > > ;; > > ;; == Permutation > > ;; ---- [INT,FP] General permutes > > @@ -2312,6 +2313,47 @@ (define_insn "@aarch64_sve_<optab><mode>" > > "<sve_int_op>\t%0.<Vewtype>, %1.<Vetype>, %2.<Vetype>" > > ) > > > > +;; > > +--------------------------------------------------------------------- > > +-- > > +-- ;; ---- [INT] Misc optab implementations ;; > > +--------------------------------------------------------------------- > > +-- > > +-- > > +;; Includes: > > +;; - aarch64_bitmask_udiv > > +;; > > +--------------------------------------------------------------------- > > +-- > > +-- > > + > > +;; div optimizations using narrowings ;; we can do the division e.g. > > +shorts by 255 faster by calculating it as ;; (x + ((x + 257) >> 8)) > > +>> 8 assuming the operation is done in ;; double the precision of x. > > +;; > > +;; See aarch64-simd.md for bigger explanation. > > +(define_expand "@aarch64_bitmask_udiv<mode>3" > > + [(match_operand:SVE_FULL_HSDI 0 "register_operand") > > + (match_operand:SVE_FULL_HSDI 1 "register_operand") > > + (match_operand:SVE_FULL_HSDI 2 "immediate_operand")] > > + "TARGET_SVE2" > > +{ > > + unsigned HOST_WIDE_INT size > > + = (1ULL << GET_MODE_UNIT_BITSIZE (<VNARROW>mode)) - 1; > > + if (!CONST_VECTOR_P (operands[2]) > > + || const_vector_encoded_nelts (operands[2]) != 1 > > + || size != UINTVAL (CONST_VECTOR_ELT (operands[2], 0))) > > + FAIL; > > + > > + rtx addend = gen_reg_rtx (<MODE>mode); > > + rtx tmp1 = gen_reg_rtx (<VNARROW>mode); > > + rtx tmp2 = gen_reg_rtx (<VNARROW>mode); > > + rtx val = aarch64_simd_gen_const_vector_dup (<VNARROW>mode, 1); > > + emit_move_insn (addend, lowpart_subreg (<MODE>mode, val, > > +<VNARROW>mode)); > > + emit_insn (gen_aarch64_sve (UNSPEC_ADDHNB, <MODE>mode, tmp1, > > operands[1], > > + addend)); > > + emit_insn (gen_aarch64_sve (UNSPEC_ADDHNB, <MODE>mode, tmp2, > > operands[1], > > + lowpart_subreg (<MODE>mode, tmp1, > > + <VNARROW>mode))); > > + emit_move_insn (operands[0], > > + lowpart_subreg (<MODE>mode, tmp2, > > <VNARROW>mode)); > > + DONE; > > +}) > > + > > ;; > > > ========================================================== > > =============== > > ;; == Permutation > > ;; > > > ========================================================== > > =============== > > diff --git a/gcc/testsuite/gcc.target/aarch64/sve2/div-by-bitmask_1.c > > b/gcc/testsuite/gcc.target/aarch64/sve2/div-by-bitmask_1.c > > new file mode 100644 > > index > > > 0000000000000000000000000000000000000000..e6f5098c30f4e2eb8ed1af153c > > 0bb0d204cda6d9 > > --- /dev/null > > +++ b/gcc/testsuite/gcc.target/aarch64/sve2/div-by-bitmask_1.c > > @@ -0,0 +1,53 @@ > > +/* { dg-do compile } */ > > +/* { dg-additional-options "-O2 -std=c99" } */ > > +/* { dg-final { check-function-bodies "**" "" "" { target { le } } } > > +} */ > > + > > +#include <stdint.h> > > + > > +/* > > +** draw_bitmap1: > > +** ... > > +** mul z[0-9]+.h, p[0-9]+/m, z[0-9]+.h, z[0-9]+.h > > +** addhnb z[0-9]+.b, z[0-9]+.h, z[0-9]+.h > > +** addhnb z[0-9]+.b, z[0-9]+.h, z[0-9]+.h > > +** ... > > +*/ > > +void draw_bitmap1(uint8_t* restrict pixel, uint8_t level, int n) { > > + for (int i = 0; i < (n & -16); i+=1) > > + pixel[i] = (pixel[i] * level) / 0xff; } > > + > > +void draw_bitmap2(uint8_t* restrict pixel, uint8_t level, int n) { > > + for (int i = 0; i < (n & -16); i+=1) > > + pixel[i] = (pixel[i] * level) / 0xfe; } > > + > > +/* > > +** draw_bitmap3: > > +** ... > > +** mul z[0-9]+.s, p[0-9]+/m, z[0-9]+.s, z[0-9]+.s > > +** addhnb z[0-9]+.h, z[0-9]+.s, z[0-9]+.s > > +** addhnb z[0-9]+.h, z[0-9]+.s, z[0-9]+.s > > +** ... > > +*/ > > +void draw_bitmap3(uint16_t* restrict pixel, uint16_t level, int n) { > > + for (int i = 0; i < (n & -16); i+=1) > > + pixel[i] = (pixel[i] * level) / 0xffffU; } > > + > > +/* > > +** draw_bitmap4: > > +** ... > > +** mul z[0-9]+.d, p[0-9]+/m, z[0-9]+.d, z[0-9]+.d > > +** addhnb z[0-9]+.s, z[0-9]+.d, z[0-9]+.d > > +** addhnb z[0-9]+.s, z[0-9]+.d, z[0-9]+.d > > +** ... > > +*/ > > +void draw_bitmap4(uint32_t* restrict pixel, uint32_t level, int n) { > > + for (int i = 0; i < (n & -16); i+=1) > > + pixel[i] = (pixel[i] * (uint64_t)level) / 0xffffffffUL; } > > > > > > > > > > --