Update move expanders to convert the CONST_WIDE_INT operand to vector broadcast from a byte with AVX2. Add ix86_gen_scratch_sse_rtx to return a scratch SSE register which won't increase stack alignment requirement and blocks transformation by the combine pass.
A small benchmark: https://gitlab.com/x86-benchmarks/microbenchmark/-/tree/memset/broadcast shows that broadcast is a little bit faster on Intel Core i7-8559U: $ make gcc -g -I. -O2 -c -o test.o test.c gcc -g -c -o memory.o memory.S gcc -g -c -o broadcast.o broadcast.S gcc -o test test.o memory.o broadcast.o ./test memory : 99333 broadcast: 97208 $ broadcast is also smaller: $ size memory.o broadcast.o text data bss dec hex filename 132 0 0 132 84 memory.o 122 0 0 122 7a broadcast.o $ gcc/ PR target/100865 * config/i386/i386-expand.c (ix86_expand_vector_init_duplicate): New prototype. (ix86_byte_broadcast): New function. (ix86_convert_const_wide_int_to_broadcast): Likewise. (ix86_expand_move): Try ix86_convert_const_wide_int_to_broadcast if mode size is 16 bytes or bigger. (ix86_expand_vector_move): Try ix86_convert_const_wide_int_to_broadcast. * config/i386/i386-protos.h (ix86_gen_scratch_sse_rtx): New prototype. * config/i386/i386.c (ix86_minimum_incoming_stack_boundary): Add an argument to ignore stack_alignment_estimated. It is passed as false by default. (ix86_gen_scratch_sse_rtx): New function. gcc/testsuite/ PR target/100865 * gcc.target/i386/pr100865-1.c: New test. * gcc.target/i386/pr100865-2.c: Likewise. * gcc.target/i386/pr100865-3.c: Likewise. * gcc.target/i386/pr100865-4.c: Likewise. * gcc.target/i386/pr100865-5.c: Likewise. --- gcc/config/i386/i386-expand.c | 103 ++++++++++++++++++--- gcc/config/i386/i386-protos.h | 2 + gcc/config/i386/i386.c | 50 +++++++++- gcc/testsuite/gcc.target/i386/pr100865-1.c | 13 +++ gcc/testsuite/gcc.target/i386/pr100865-2.c | 14 +++ gcc/testsuite/gcc.target/i386/pr100865-3.c | 15 +++ gcc/testsuite/gcc.target/i386/pr100865-4.c | 16 ++++ gcc/testsuite/gcc.target/i386/pr100865-5.c | 17 ++++ 8 files changed, 215 insertions(+), 15 deletions(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr100865-1.c create mode 100644 gcc/testsuite/gcc.target/i386/pr100865-2.c create mode 100644 gcc/testsuite/gcc.target/i386/pr100865-3.c create mode 100644 gcc/testsuite/gcc.target/i386/pr100865-4.c create mode 100644 gcc/testsuite/gcc.target/i386/pr100865-5.c diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c index 4185f58eed5..658adafa269 100644 --- a/gcc/config/i386/i386-expand.c +++ b/gcc/config/i386/i386-expand.c @@ -93,6 +93,9 @@ along with GCC; see the file COPYING3. If not see #include "i386-builtins.h" #include "i386-expand.h" +static bool ix86_expand_vector_init_duplicate (bool, machine_mode, rtx, + rtx); + /* Split one or more double-mode RTL references into pairs of half-mode references. The RTL can be REG, offsettable MEM, integer constant, or CONST_DOUBLE. "operands" is a pointer to an array of double-mode RTLs to @@ -190,6 +193,65 @@ ix86_expand_clear (rtx dest) emit_insn (tmp); } +/* Return a byte value which V can be broadcasted from. Otherwise, + return INT_MAX. */ + +static int +ix86_byte_broadcast (HOST_WIDE_INT v) +{ + wide_int val = wi::uhwi (v, HOST_BITS_PER_WIDE_INT); + int byte_broadcast = wi::extract_uhwi (val, 0, BITS_PER_UNIT); + for (unsigned int i = BITS_PER_UNIT; + i < HOST_BITS_PER_WIDE_INT; + i += BITS_PER_UNIT) + { + int byte = wi::extract_uhwi (val, i, BITS_PER_UNIT); + if (byte_broadcast != byte) + return INT_MAX; + } + return byte_broadcast; +} + +/* Convert the CONST_WIDE_INT operand OP to broadcast in MODE. */ + +static rtx +ix86_convert_const_wide_int_to_broadcast (machine_mode mode, rtx op) +{ + rtx target = nullptr; + + /* Convert CONST_WIDE_INT to broadcast only if vector broadcast is + available. */ + if (!TARGET_AVX2 || !CONST_WIDE_INT_P (op)) + return target; + + HOST_WIDE_INT val = CONST_WIDE_INT_ELT (op, 0); + int byte_broadcast = ix86_byte_broadcast (val); + + if (byte_broadcast == INT_MAX) + return target; + + /* Check if OP1 can be broadcasted from VAL. */ + for (int i = 1; i < CONST_WIDE_INT_NUNITS (op); i++) + if (val != CONST_WIDE_INT_ELT (op, i)) + return target; + + unsigned int nunits = GET_MODE_SIZE (mode) / GET_MODE_SIZE (QImode); + machine_mode vector_mode; + if (!mode_for_vector (QImode, nunits).exists (&vector_mode)) + gcc_unreachable (); + target = ix86_gen_scratch_sse_rtx (vector_mode, true); + rtx byte = GEN_INT ((char) byte_broadcast); + if (!ix86_expand_vector_init_duplicate (false, vector_mode, target, + byte)) + gcc_unreachable (); + if (REGNO (target) < FIRST_PSEUDO_REGISTER) + target = gen_rtx_REG (mode, REGNO (target)); + else + target = convert_to_mode (mode, target, 1); + + return target; +} + void ix86_expand_move (machine_mode mode, rtx operands[]) { @@ -347,20 +409,29 @@ ix86_expand_move (machine_mode mode, rtx operands[]) && optimize) op1 = copy_to_mode_reg (mode, op1); - if (can_create_pseudo_p () - && CONST_DOUBLE_P (op1)) + if (can_create_pseudo_p ()) { - /* If we are loading a floating point constant to a register, - force the value to memory now, since we'll get better code - out the back end. */ + if (CONST_DOUBLE_P (op1)) + { + /* If we are loading a floating point constant to a + register, force the value to memory now, since we'll + get better code out the back end. */ - op1 = validize_mem (force_const_mem (mode, op1)); - if (!register_operand (op0, mode)) + op1 = validize_mem (force_const_mem (mode, op1)); + if (!register_operand (op0, mode)) + { + rtx temp = gen_reg_rtx (mode); + emit_insn (gen_rtx_SET (temp, op1)); + emit_move_insn (op0, temp); + return; + } + } + else if (GET_MODE_SIZE (mode) >= 16) { - rtx temp = gen_reg_rtx (mode); - emit_insn (gen_rtx_SET (temp, op1)); - emit_move_insn (op0, temp); - return; + rtx tmp = ix86_convert_const_wide_int_to_broadcast + (GET_MODE (op0), op1); + if (tmp != nullptr) + op1 = tmp; } } } @@ -407,7 +478,15 @@ ix86_expand_vector_move (machine_mode mode, rtx operands[]) op1 = simplify_gen_subreg (mode, r, imode, SUBREG_BYTE (op1)); } else - op1 = validize_mem (force_const_mem (mode, op1)); + { + machine_mode mode = GET_MODE (op0); + rtx tmp = ix86_convert_const_wide_int_to_broadcast + (mode, op1); + if (tmp == nullptr) + op1 = validize_mem (force_const_mem (mode, op1)); + else + op1 = tmp; + } } /* We need to check memory alignment for SSE mode since attribute diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h index 7782cf1163f..01b3775df92 100644 --- a/gcc/config/i386/i386-protos.h +++ b/gcc/config/i386/i386-protos.h @@ -50,6 +50,8 @@ extern void ix86_reset_previous_fndecl (void); extern bool ix86_using_red_zone (void); +extern rtx ix86_gen_scratch_sse_rtx (machine_mode, bool); + extern unsigned int ix86_regmode_natural_size (machine_mode); #ifdef RTX_CODE extern int standard_80387_constant_p (rtx); diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 04649b42122..3595fb5778e 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -415,7 +415,8 @@ static unsigned int split_stack_prologue_scratch_regno (void); static bool i386_asm_output_addr_const_extra (FILE *, rtx); static bool ix86_can_inline_p (tree, tree); -static unsigned int ix86_minimum_incoming_stack_boundary (bool); +static unsigned int ix86_minimum_incoming_stack_boundary (bool, + bool = false); /* Whether -mtune= or -march= were specified */ @@ -7232,7 +7233,8 @@ find_drap_reg (void) /* Return minimum incoming stack alignment. */ static unsigned int -ix86_minimum_incoming_stack_boundary (bool sibcall) +ix86_minimum_incoming_stack_boundary (bool sibcall, + bool ignore_estimated) { unsigned int incoming_stack_boundary; @@ -7247,7 +7249,8 @@ ix86_minimum_incoming_stack_boundary (bool sibcall) estimated stack alignment is 128bit. */ else if (!sibcall && ix86_force_align_arg_pointer - && crtl->stack_alignment_estimated == 128) + && (ignore_estimated + || crtl->stack_alignment_estimated == 128)) incoming_stack_boundary = MIN_STACK_BOUNDARY; else incoming_stack_boundary = ix86_default_incoming_stack_boundary; @@ -23061,6 +23064,47 @@ ix86_optab_supported_p (int op, machine_mode mode1, machine_mode, } } +/* Return a scratch register in MODE for vector load and store. If + CONSTANT_BROADCAST is true, it is used to hold constant broadcast + result. */ + +rtx +ix86_gen_scratch_sse_rtx (machine_mode mode, bool constant_broadcast) +{ + bool need_hard_reg = false; + + /* NB: Choose a hard scratch SSE register: + 1. Avoid increasing stack alignment requirement. + 2. for constant broadcast in 64-bit mode, avoid transformation by + the combine pass. + */ + if (GET_MODE_SIZE (mode) >= 16 + && !COMPLEX_MODE_P (mode) + && (SCALAR_INT_MODE_P (mode) || VECTOR_MODE_P (mode))) + { + if (constant_broadcast + && TARGET_64BIT + && GET_MODE_SIZE (mode) == 16) + need_hard_reg = true; + else + { + unsigned int incoming_stack_boundary + = ix86_minimum_incoming_stack_boundary (false, true); + if (GET_MODE_ALIGNMENT (mode) > incoming_stack_boundary) + need_hard_reg = true; + } + } + + rtx target; + if (need_hard_reg) + target = gen_rtx_REG (mode, (TARGET_64BIT + ? LAST_REX_SSE_REG + : LAST_SSE_REG)); + else + target = gen_reg_rtx (mode); + return target; +} + /* Address space support. This is not "far pointers" in the 16-bit sense, but an easy way diff --git a/gcc/testsuite/gcc.target/i386/pr100865-1.c b/gcc/testsuite/gcc.target/i386/pr100865-1.c new file mode 100644 index 00000000000..6c3097fb2a6 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr100865-1.c @@ -0,0 +1,13 @@ +/* { dg-do compile { target { ! ia32 } } } */ +/* { dg-options "-O2 -march=x86-64" } */ + +extern char *dst; + +void +foo (void) +{ + __builtin_memset (dst, 3, 16); +} + +/* { dg-final { scan-assembler-times "movdqa\[ \\t\]+\[^\n\]*%xmm" 1 } } */ +/* { dg-final { scan-assembler-times "movups\[\\t \]%xmm\[0-9\]+, \\(%\[\^,\]+\\)" 1 } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr100865-2.c b/gcc/testsuite/gcc.target/i386/pr100865-2.c new file mode 100644 index 00000000000..17efe2d72a3 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr100865-2.c @@ -0,0 +1,14 @@ +/* { dg-do compile { target { ! ia32 } } } */ +/* { dg-options "-O2 -march=skylake" } */ + +extern char *dst; + +void +foo (void) +{ + __builtin_memset (dst, 3, 16); +} + +/* { dg-final { scan-assembler-times "vpbroadcastb\[\\t \]+%xmm\[0-9\]+, %xmm\[0-9\]+" 1 } } */ +/* { dg-final { scan-assembler-times "vmovdqu\[\\t \]%xmm\[0-9\]+, \\(%\[\^,\]+\\)" 1 } } */ +/* { dg-final { scan-assembler-not "vmovdqa" } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr100865-3.c b/gcc/testsuite/gcc.target/i386/pr100865-3.c new file mode 100644 index 00000000000..56665d8c9b6 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr100865-3.c @@ -0,0 +1,15 @@ +/* { dg-do compile { target { ! ia32 } } } */ +/* { dg-options "-O2 -march=skylake-avx512" } */ + +extern char *dst; + +void +foo (void) +{ + __builtin_memset (dst, 3, 16); +} + +/* { dg-final { scan-assembler-times "vpbroadcastb\[\\t \]+%.*, %xmm\[0-9\]+" 1 } } */ +/* { dg-final { scan-assembler-times "vmovdqu\[\\t \]%xmm\[0-9\]+, \\(%\[\^,\]+\\)" 1 } } */ +/* { dg-final { scan-assembler-not "vpbroadcastb\[\\t \]+%xmm\[0-9\]+, %xmm\[0-9\]+" } } */ +/* { dg-final { scan-assembler-not "vmovdqa" } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr100865-4.c b/gcc/testsuite/gcc.target/i386/pr100865-4.c new file mode 100644 index 00000000000..1622a06f57e --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr100865-4.c @@ -0,0 +1,16 @@ +/* { dg-do compile { target { ! ia32 } } } */ +/* { dg-options "-O2 -march=skylake" } */ + +extern char array[64]; + +void +foo (void) +{ + int i; + for (i = 0; i < 64; i++) + array[i] = -45; +} + +/* { dg-final { scan-assembler-times "vpbroadcastb\[\\t \]+%xmm\[0-9\]+, %xmm\[0-9\]+" 1 } } */ +/* { dg-final { scan-assembler-times "vmovdqu\[\\t \]%xmm\[0-9\]+, " 4 } } */ +/* { dg-final { scan-assembler-not "vmovdqa" } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr100865-5.c b/gcc/testsuite/gcc.target/i386/pr100865-5.c new file mode 100644 index 00000000000..66040d9f972 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr100865-5.c @@ -0,0 +1,17 @@ +/* { dg-do compile { target { ! ia32 } } } */ +/* { dg-options "-O2 -march=skylake-avx512" } */ + +extern char array[64]; + +void +foo (void) +{ + int i; + for (i = 0; i < 64; i++) + array[i] = -45; +} + +/* { dg-final { scan-assembler-times "vpbroadcastb\[\\t \]+%.*, %xmm\[0-9\]+" 1 } } */ +/* { dg-final { scan-assembler-times "vmovdqu\[\\t \]%xmm\[0-9\]+, " 4 } } */ +/* { dg-final { scan-assembler-not "vpbroadcastb\[\\t \]+%xmm\[0-9\]+, %xmm\[0-9\]+" } } */ +/* { dg-final { scan-assembler-not "vmovdqa" } } */ -- 2.31.1
