| Message ID | 20210419213605.2851266-1-goldstein.w.n@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v4,1/2] x86: Optimize less_vec evex and avx512 memset-vec-unaligned-erms.S | expand |
On Mon, Apr 19, 2021 at 2:36 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote: > > No bug. This commit adds optimized cased for less_vec memset case that > uses the avx512vl/avx512bw mask store avoiding the excessive > branches. test-memset and test-wmemset are passing. > > Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> > --- > sysdeps/x86_64/multiarch/ifunc-impl-list.c | 40 ++++++++++----- > sysdeps/x86_64/multiarch/ifunc-memset.h | 6 ++- > .../multiarch/memset-avx512-unaligned-erms.S | 2 +- > .../multiarch/memset-evex-unaligned-erms.S | 2 +- > .../multiarch/memset-vec-unaligned-erms.S | 51 +++++++++++++++---- > 5 files changed, 74 insertions(+), 27 deletions(-) > > diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c > index 0b0927b124..c377cab629 100644 > --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c > +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c > @@ -204,19 +204,23 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, > __memset_chk_avx2_unaligned_erms_rtm) > IFUNC_IMPL_ADD (array, i, __memset_chk, > (CPU_FEATURE_USABLE (AVX512VL) > - && CPU_FEATURE_USABLE (AVX512BW)), > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __memset_chk_evex_unaligned) > IFUNC_IMPL_ADD (array, i, __memset_chk, > (CPU_FEATURE_USABLE (AVX512VL) > - && CPU_FEATURE_USABLE (AVX512BW)), > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __memset_chk_evex_unaligned_erms) > IFUNC_IMPL_ADD (array, i, __memset_chk, > (CPU_FEATURE_USABLE (AVX512VL) > - && CPU_FEATURE_USABLE (AVX512BW)), > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __memset_chk_avx512_unaligned_erms) > IFUNC_IMPL_ADD (array, i, __memset_chk, > (CPU_FEATURE_USABLE (AVX512VL) > - && CPU_FEATURE_USABLE (AVX512BW)), > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __memset_chk_avx512_unaligned) > IFUNC_IMPL_ADD (array, i, __memset_chk, > CPU_FEATURE_USABLE (AVX512F), > @@ -247,19 +251,23 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, > __memset_avx2_unaligned_erms_rtm) > IFUNC_IMPL_ADD (array, i, memset, > (CPU_FEATURE_USABLE (AVX512VL) > - && CPU_FEATURE_USABLE (AVX512BW)), > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __memset_evex_unaligned) > IFUNC_IMPL_ADD (array, i, memset, > (CPU_FEATURE_USABLE (AVX512VL) > - && CPU_FEATURE_USABLE (AVX512BW)), > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __memset_evex_unaligned_erms) > IFUNC_IMPL_ADD (array, i, memset, > (CPU_FEATURE_USABLE (AVX512VL) > - && CPU_FEATURE_USABLE (AVX512BW)), > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __memset_avx512_unaligned_erms) > IFUNC_IMPL_ADD (array, i, memset, > (CPU_FEATURE_USABLE (AVX512VL) > - && CPU_FEATURE_USABLE (AVX512BW)), > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __memset_avx512_unaligned) > IFUNC_IMPL_ADD (array, i, memset, > CPU_FEATURE_USABLE (AVX512F), > @@ -728,10 +736,14 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, > && CPU_FEATURE_USABLE (RTM)), > __wmemset_avx2_unaligned_rtm) > IFUNC_IMPL_ADD (array, i, wmemset, > - CPU_FEATURE_USABLE (AVX512VL), > + (CPU_FEATURE_USABLE (AVX512VL) > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __wmemset_evex_unaligned) > IFUNC_IMPL_ADD (array, i, wmemset, > - CPU_FEATURE_USABLE (AVX512VL), > + (CPU_FEATURE_USABLE (AVX512VL) > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __wmemset_avx512_unaligned)) > > #ifdef SHARED > @@ -935,10 +947,14 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, > CPU_FEATURE_USABLE (AVX2), > __wmemset_chk_avx2_unaligned) > IFUNC_IMPL_ADD (array, i, __wmemset_chk, > - CPU_FEATURE_USABLE (AVX512VL), > + (CPU_FEATURE_USABLE (AVX512VL) > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __wmemset_chk_evex_unaligned) > IFUNC_IMPL_ADD (array, i, __wmemset_chk, > - CPU_FEATURE_USABLE (AVX512F), > + (CPU_FEATURE_USABLE (AVX512VL) > + && CPU_FEATURE_USABLE (AVX512BW) > + && CPU_FEATURE_USABLE (BMI2)), > __wmemset_chk_avx512_unaligned)) > #endif > > diff --git a/sysdeps/x86_64/multiarch/ifunc-memset.h b/sysdeps/x86_64/multiarch/ifunc-memset.h > index 502f946a84..eda5640541 100644 > --- a/sysdeps/x86_64/multiarch/ifunc-memset.h > +++ b/sysdeps/x86_64/multiarch/ifunc-memset.h > @@ -54,7 +54,8 @@ IFUNC_SELECTOR (void) > && !CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_AVX512)) > { > if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL) > - && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)) > + && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW) > + && CPU_FEATURE_USABLE_P (cpu_features, BMI2)) > { > if (CPU_FEATURE_USABLE_P (cpu_features, ERMS)) > return OPTIMIZE (avx512_unaligned_erms); > @@ -68,7 +69,8 @@ IFUNC_SELECTOR (void) > if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)) > { > if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL) > - && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)) > + && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW) > + && CPU_FEATURE_USABLE_P (cpu_features, BMI2)) > { > if (CPU_FEATURE_USABLE_P (cpu_features, ERMS)) > return OPTIMIZE (evex_unaligned_erms); > diff --git a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S > index 22e7b187c8..8ad842fc2f 100644 > --- a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S > +++ b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S > @@ -19,6 +19,6 @@ > # define SECTION(p) p##.evex512 > # define MEMSET_SYMBOL(p,s) p##_avx512_##s > # define WMEMSET_SYMBOL(p,s) p##_avx512_##s > - > +# define USE_LESS_VEC_MASK_STORE 1 > # include "memset-vec-unaligned-erms.S" > #endif > diff --git a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S > index ae0a4d6e46..640f092903 100644 > --- a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S > +++ b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S > @@ -19,6 +19,6 @@ > # define SECTION(p) p##.evex > # define MEMSET_SYMBOL(p,s) p##_evex_##s > # define WMEMSET_SYMBOL(p,s) p##_evex_##s > - > +# define USE_LESS_VEC_MASK_STORE 1 > # include "memset-vec-unaligned-erms.S" > #endif > diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S > index 584747f1a1..4eac39326e 100644 > --- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S > +++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S > @@ -63,6 +63,8 @@ > # endif > #endif > > +#define PAGE_SIZE 4096 > + > #ifndef SECTION > # error SECTION is not defined! > #endif > @@ -213,11 +215,38 @@ L(loop): > cmpq %rcx, %rdx > jne L(loop) > VZEROUPPER_SHORT_RETURN > + > + .p2align 4 > L(less_vec): > /* Less than 1 VEC. */ > # if VEC_SIZE != 16 && VEC_SIZE != 32 && VEC_SIZE != 64 > # error Unsupported VEC_SIZE! > # endif > +# ifdef USE_LESS_VEC_MASK_STORE > + /* Clear high bits from edi. Only keeping bits relevant to page > + cross check. Note that we are using rax which is set in > + MEMSET_VDUP_TO_VEC0_AND_SET_RETURN as ptr from here on out. > + */ > + andl $(PAGE_SIZE - 1), %edi > + /* Check if VEC_SIZE load cross page. Mask loads suffer serious It should be store, not load. > + performance degradation when it has to fault supress. */ > + cmpl $(PAGE_SIZE - VEC_SIZE), %edi > + ja L(cross_page) > +# if VEC_SIZE > 32 > + movq $-1, %rcx > + bzhiq %rdx, %rcx, %rcx > + kmovq %rcx, %k1 > +# else > + movl $-1, %ecx > + bzhil %edx, %ecx, %ecx > + kmovd %ecx, %k1 > +# endif > + vmovdqu8 %VEC(0), (%rax) {%k1} > + VZEROUPPER_RETURN > + > + .p2align 4 > +L(cross_page): > +# endif > # if VEC_SIZE > 32 > cmpb $32, %dl > jae L(between_32_63) > @@ -234,36 +263,36 @@ L(less_vec): > cmpb $1, %dl > ja L(between_2_3) > jb 1f > - movb %cl, (%rdi) > + movb %cl, (%rax) > 1: > VZEROUPPER_RETURN > # if VEC_SIZE > 32 > /* From 32 to 63. No branch when size == 32. */ > L(between_32_63): > - VMOVU %YMM0, -32(%rdi,%rdx) > - VMOVU %YMM0, (%rdi) > + VMOVU %YMM0, -32(%rax,%rdx) > + VMOVU %YMM0, (%rax) > VZEROUPPER_RETURN > # endif > # if VEC_SIZE > 16 > /* From 16 to 31. No branch when size == 16. */ > L(between_16_31): > - VMOVU %XMM0, -16(%rdi,%rdx) > - VMOVU %XMM0, (%rdi) > + VMOVU %XMM0, -16(%rax,%rdx) > + VMOVU %XMM0, (%rax) > VZEROUPPER_RETURN > # endif > /* From 8 to 15. No branch when size == 8. */ > L(between_8_15): > - movq %rcx, -8(%rdi,%rdx) > - movq %rcx, (%rdi) > + movq %rcx, -8(%rax,%rdx) > + movq %rcx, (%rax) > VZEROUPPER_RETURN > L(between_4_7): > /* From 4 to 7. No branch when size == 4. */ > - movl %ecx, -4(%rdi,%rdx) > - movl %ecx, (%rdi) > + movl %ecx, -4(%rax,%rdx) > + movl %ecx, (%rax) > VZEROUPPER_RETURN > L(between_2_3): > /* From 2 to 3. No branch when size == 2. */ > - movw %cx, -2(%rdi,%rdx) > - movw %cx, (%rdi) > + movw %cx, -2(%rax,%rdx) > + movw %cx, (%rax) > VZEROUPPER_RETURN > END (MEMSET_SYMBOL (__memset, unaligned_erms)) > -- > 2.29.2 >
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c index 0b0927b124..c377cab629 100644 --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c @@ -204,19 +204,23 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, __memset_chk_avx2_unaligned_erms_rtm) IFUNC_IMPL_ADD (array, i, __memset_chk, (CPU_FEATURE_USABLE (AVX512VL) - && CPU_FEATURE_USABLE (AVX512BW)), + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __memset_chk_evex_unaligned) IFUNC_IMPL_ADD (array, i, __memset_chk, (CPU_FEATURE_USABLE (AVX512VL) - && CPU_FEATURE_USABLE (AVX512BW)), + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __memset_chk_evex_unaligned_erms) IFUNC_IMPL_ADD (array, i, __memset_chk, (CPU_FEATURE_USABLE (AVX512VL) - && CPU_FEATURE_USABLE (AVX512BW)), + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __memset_chk_avx512_unaligned_erms) IFUNC_IMPL_ADD (array, i, __memset_chk, (CPU_FEATURE_USABLE (AVX512VL) - && CPU_FEATURE_USABLE (AVX512BW)), + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __memset_chk_avx512_unaligned) IFUNC_IMPL_ADD (array, i, __memset_chk, CPU_FEATURE_USABLE (AVX512F), @@ -247,19 +251,23 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, __memset_avx2_unaligned_erms_rtm) IFUNC_IMPL_ADD (array, i, memset, (CPU_FEATURE_USABLE (AVX512VL) - && CPU_FEATURE_USABLE (AVX512BW)), + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __memset_evex_unaligned) IFUNC_IMPL_ADD (array, i, memset, (CPU_FEATURE_USABLE (AVX512VL) - && CPU_FEATURE_USABLE (AVX512BW)), + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __memset_evex_unaligned_erms) IFUNC_IMPL_ADD (array, i, memset, (CPU_FEATURE_USABLE (AVX512VL) - && CPU_FEATURE_USABLE (AVX512BW)), + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __memset_avx512_unaligned_erms) IFUNC_IMPL_ADD (array, i, memset, (CPU_FEATURE_USABLE (AVX512VL) - && CPU_FEATURE_USABLE (AVX512BW)), + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __memset_avx512_unaligned) IFUNC_IMPL_ADD (array, i, memset, CPU_FEATURE_USABLE (AVX512F), @@ -728,10 +736,14 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, && CPU_FEATURE_USABLE (RTM)), __wmemset_avx2_unaligned_rtm) IFUNC_IMPL_ADD (array, i, wmemset, - CPU_FEATURE_USABLE (AVX512VL), + (CPU_FEATURE_USABLE (AVX512VL) + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __wmemset_evex_unaligned) IFUNC_IMPL_ADD (array, i, wmemset, - CPU_FEATURE_USABLE (AVX512VL), + (CPU_FEATURE_USABLE (AVX512VL) + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __wmemset_avx512_unaligned)) #ifdef SHARED @@ -935,10 +947,14 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, CPU_FEATURE_USABLE (AVX2), __wmemset_chk_avx2_unaligned) IFUNC_IMPL_ADD (array, i, __wmemset_chk, - CPU_FEATURE_USABLE (AVX512VL), + (CPU_FEATURE_USABLE (AVX512VL) + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __wmemset_chk_evex_unaligned) IFUNC_IMPL_ADD (array, i, __wmemset_chk, - CPU_FEATURE_USABLE (AVX512F), + (CPU_FEATURE_USABLE (AVX512VL) + && CPU_FEATURE_USABLE (AVX512BW) + && CPU_FEATURE_USABLE (BMI2)), __wmemset_chk_avx512_unaligned)) #endif diff --git a/sysdeps/x86_64/multiarch/ifunc-memset.h b/sysdeps/x86_64/multiarch/ifunc-memset.h index 502f946a84..eda5640541 100644 --- a/sysdeps/x86_64/multiarch/ifunc-memset.h +++ b/sysdeps/x86_64/multiarch/ifunc-memset.h @@ -54,7 +54,8 @@ IFUNC_SELECTOR (void) && !CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_AVX512)) { if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL) - && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)) + && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW) + && CPU_FEATURE_USABLE_P (cpu_features, BMI2)) { if (CPU_FEATURE_USABLE_P (cpu_features, ERMS)) return OPTIMIZE (avx512_unaligned_erms); @@ -68,7 +69,8 @@ IFUNC_SELECTOR (void) if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)) { if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL) - && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)) + && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW) + && CPU_FEATURE_USABLE_P (cpu_features, BMI2)) { if (CPU_FEATURE_USABLE_P (cpu_features, ERMS)) return OPTIMIZE (evex_unaligned_erms); diff --git a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S index 22e7b187c8..8ad842fc2f 100644 --- a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S +++ b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S @@ -19,6 +19,6 @@ # define SECTION(p) p##.evex512 # define MEMSET_SYMBOL(p,s) p##_avx512_##s # define WMEMSET_SYMBOL(p,s) p##_avx512_##s - +# define USE_LESS_VEC_MASK_STORE 1 # include "memset-vec-unaligned-erms.S" #endif diff --git a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S index ae0a4d6e46..640f092903 100644 --- a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S +++ b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S @@ -19,6 +19,6 @@ # define SECTION(p) p##.evex # define MEMSET_SYMBOL(p,s) p##_evex_##s # define WMEMSET_SYMBOL(p,s) p##_evex_##s - +# define USE_LESS_VEC_MASK_STORE 1 # include "memset-vec-unaligned-erms.S" #endif diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S index 584747f1a1..4eac39326e 100644 --- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S +++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S @@ -63,6 +63,8 @@ # endif #endif +#define PAGE_SIZE 4096 + #ifndef SECTION # error SECTION is not defined! #endif @@ -213,11 +215,38 @@ L(loop): cmpq %rcx, %rdx jne L(loop) VZEROUPPER_SHORT_RETURN + + .p2align 4 L(less_vec): /* Less than 1 VEC. */ # if VEC_SIZE != 16 && VEC_SIZE != 32 && VEC_SIZE != 64 # error Unsupported VEC_SIZE! # endif +# ifdef USE_LESS_VEC_MASK_STORE + /* Clear high bits from edi. Only keeping bits relevant to page + cross check. Note that we are using rax which is set in + MEMSET_VDUP_TO_VEC0_AND_SET_RETURN as ptr from here on out. + */ + andl $(PAGE_SIZE - 1), %edi + /* Check if VEC_SIZE load cross page. Mask loads suffer serious + performance degradation when it has to fault supress. */ + cmpl $(PAGE_SIZE - VEC_SIZE), %edi + ja L(cross_page) +# if VEC_SIZE > 32 + movq $-1, %rcx + bzhiq %rdx, %rcx, %rcx + kmovq %rcx, %k1 +# else + movl $-1, %ecx + bzhil %edx, %ecx, %ecx + kmovd %ecx, %k1 +# endif + vmovdqu8 %VEC(0), (%rax) {%k1} + VZEROUPPER_RETURN + + .p2align 4 +L(cross_page): +# endif # if VEC_SIZE > 32 cmpb $32, %dl jae L(between_32_63) @@ -234,36 +263,36 @@ L(less_vec): cmpb $1, %dl ja L(between_2_3) jb 1f - movb %cl, (%rdi) + movb %cl, (%rax) 1: VZEROUPPER_RETURN # if VEC_SIZE > 32 /* From 32 to 63. No branch when size == 32. */ L(between_32_63): - VMOVU %YMM0, -32(%rdi,%rdx) - VMOVU %YMM0, (%rdi) + VMOVU %YMM0, -32(%rax,%rdx) + VMOVU %YMM0, (%rax) VZEROUPPER_RETURN # endif # if VEC_SIZE > 16 /* From 16 to 31. No branch when size == 16. */ L(between_16_31): - VMOVU %XMM0, -16(%rdi,%rdx) - VMOVU %XMM0, (%rdi) + VMOVU %XMM0, -16(%rax,%rdx) + VMOVU %XMM0, (%rax) VZEROUPPER_RETURN # endif /* From 8 to 15. No branch when size == 8. */ L(between_8_15): - movq %rcx, -8(%rdi,%rdx) - movq %rcx, (%rdi) + movq %rcx, -8(%rax,%rdx) + movq %rcx, (%rax) VZEROUPPER_RETURN L(between_4_7): /* From 4 to 7. No branch when size == 4. */ - movl %ecx, -4(%rdi,%rdx) - movl %ecx, (%rdi) + movl %ecx, -4(%rax,%rdx) + movl %ecx, (%rax) VZEROUPPER_RETURN L(between_2_3): /* From 2 to 3. No branch when size == 2. */ - movw %cx, -2(%rdi,%rdx) - movw %cx, (%rdi) + movw %cx, -2(%rax,%rdx) + movw %cx, (%rax) VZEROUPPER_RETURN END (MEMSET_SYMBOL (__memset, unaligned_erms))
No bug. This commit adds optimized cased for less_vec memset case that uses the avx512vl/avx512bw mask store avoiding the excessive branches. test-memset and test-wmemset are passing. Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> --- sysdeps/x86_64/multiarch/ifunc-impl-list.c | 40 ++++++++++----- sysdeps/x86_64/multiarch/ifunc-memset.h | 6 ++- .../multiarch/memset-avx512-unaligned-erms.S | 2 +- .../multiarch/memset-evex-unaligned-erms.S | 2 +- .../multiarch/memset-vec-unaligned-erms.S | 51 +++++++++++++++---- 5 files changed, 74 insertions(+), 27 deletions(-)