On Wed, Oct 3, 2018 at 10:50 AM Wilco Dijkstra <wilco.dijks...@arm.com> wrote:
>
> Andrew Pinski wrote:
>
> > Something like will cover w->w zero-extension.
>
> Thanks, those cases trigger and show an improvement, so I've
> added r=w and w=w cases too:
>
> The popcount expansion uses SIMD instructions acting on 64-bit values.
> As a result a popcount of a 32-bit integer requires zero-extension before
> moving the zero-extended value into an FP register. This patch adds
> support for zero-extended int->FP moves to avoid the redundant uxtw.
> Similarly, add support for 32-bit zero-extending load->FP register
> and 32-bit zero-extending FP->FP and FP->int moves.
> Add a missing 'fp' arch attribute to the related 8/16-bit pattern and
> fix an incorrect type attribute.
>
> To complete zero-extended load support, add a new alternative to
> load_pair_zero_extendsidi2_aarch64 to support LDP into FP registers too.
>
> int f (int a)
> {
> return __builtin_popcount (a);
> }
>
> Before:
> uxtw x0, w0
> fmov d0, x0
> cnt v0.8b, v0.8b
> addv b0, v0.8b
> fmov w0, s0
> ret
>
> After:
> fmov s0, w0
> cnt v0.8b, v0.8b
> addv b0, v0.8b
> fmov w0, s0
> ret
>
> Passes regress on AArch64, OK for commit?
Hmm, I thought you would have added the test functions I provided to
the testsuite also to make sure they don't regress.
Thanks,
Andrew Pinski
>
> ChangeLog:
> 2018-10-03 Wilco Dijkstra <wdijk...@arm.com>
>
> gcc/
> * config/aarch64/aarch64.md (zero_extendsidi2_aarch64): Add
> alternatives
> to zero-extend between int and floating-point registers.
> (load_pair_zero_extendsidi2_aarch64): Add alternative to emit
> zero-extended
> ldp into floating-point registers. Add type and arch attributes.
> (zero_extend<SHORT:mode><GPI:mode>2_aarch64): Add arch attribute.
> Use f_loads for type attribute.
>
> testsuite/
> * gcc.target/aarch64/popcnt.c: Test zero-extended popcount.
>
> ---
>
> diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
> index
> ef2368706e88a551b9d0d2db2385860112bdbdde..5e42485a4727079cc7647f4ded45dd175030b3fb
> 100644
> --- a/gcc/config/aarch64/aarch64.md
> +++ b/gcc/config/aarch64/aarch64.md
> @@ -1588,26 +1588,34 @@ (define_insn "*load_pair_extendsidi2_aarch64"
> )
>
> (define_insn "*zero_extendsidi2_aarch64"
> - [(set (match_operand:DI 0 "register_operand" "=r,r")
> - (zero_extend:DI (match_operand:SI 1 "nonimmediate_operand" "r,m")))]
> + [(set (match_operand:DI 0 "register_operand" "=r,r,w,w,r,w")
> + (zero_extend:DI (match_operand:SI 1 "nonimmediate_operand"
> "r,m,r,m,w,w")))]
> ""
> "@
> uxtw\t%0, %w1
> - ldr\t%w0, %1"
> - [(set_attr "type" "extend,load_4")]
> + ldr\t%w0, %1
> + fmov\t%s0, %w1
> + ldr\t%s0, %1
> + fmov\t%w0, %s1
> + fmov\t%s0, %s1"
> + [(set_attr "type" "extend,load_4,f_mcr,f_loads,f_mrc,fmov")
> + (set_attr "arch" "*,*,fp,fp,fp,fp")]
> )
>
> (define_insn "*load_pair_zero_extendsidi2_aarch64"
> - [(set (match_operand:DI 0 "register_operand" "=r")
> - (zero_extend:DI (match_operand:SI 1 "aarch64_mem_pair_operand"
> "Ump")))
> - (set (match_operand:DI 2 "register_operand" "=r")
> - (zero_extend:DI (match_operand:SI 3 "memory_operand" "m")))]
> + [(set (match_operand:DI 0 "register_operand" "=r,w")
> + (zero_extend:DI (match_operand:SI 1 "aarch64_mem_pair_operand"
> "Ump,Ump")))
> + (set (match_operand:DI 2 "register_operand" "=r,w")
> + (zero_extend:DI (match_operand:SI 3 "memory_operand" "m,m")))]
> "rtx_equal_p (XEXP (operands[3], 0),
> plus_constant (Pmode,
> XEXP (operands[1], 0),
> GET_MODE_SIZE (SImode)))"
> - "ldp\\t%w0, %w2, %1"
> - [(set_attr "type" "load_8")]
> + "@
> + ldp\t%w0, %w2, %1
> + ldp\t%s0, %s2, %1"
> + [(set_attr "type" "load_8,neon_load1_2reg")
> + (set_attr "arch" "*,fp")]
> )
>
> (define_expand "<ANY_EXTEND:optab><SHORT:mode><GPI:mode>2"
> @@ -1634,7 +1642,8 @@ (define_insn
> "*zero_extend<SHORT:mode><GPI:mode>2_aarch64"
> and\t%<GPI:w>0, %<GPI:w>1, <SHORT:short_mask>
> ldr<SHORT:size>\t%w0, %1
> ldr\t%<SHORT:size>0, %1"
> - [(set_attr "type" "logic_imm,load_4,load_4")]
> + [(set_attr "type" "logic_imm,load_4,f_loads")
> + (set_attr "arch" "*,*,fp")]
> )
>
> (define_expand "<optab>qihi2"
> diff --git a/gcc/testsuite/gcc.target/aarch64/popcnt.c
> b/gcc/testsuite/gcc.target/aarch64/popcnt.c
> index
> 7e957966d8e81b8633a444bb42944d0da82ae5db..2b5e9f3e2c0245438ed7bcc5d0d4e01efe01b1ee
> 100644
> --- a/gcc/testsuite/gcc.target/aarch64/popcnt.c
> +++ b/gcc/testsuite/gcc.target/aarch64/popcnt.c
> @@ -19,5 +19,16 @@ foo2 (long long x)
> return __builtin_popcountll (x);
> }
>
> -/* { dg-final { scan-assembler-not "popcount" } } */
> -/* { dg-final { scan-assembler-times "cnt\t" 3 } } */
> +int
> +foo3 (int *p)
> +{
> + return __builtin_popcount (*p);
> +}
> +
> +/* { dg-final { scan-assembler-not {popcount} } } */
> +/* { dg-final { scan-assembler-times {cnt\t} 4 } } */
> +/* { dg-final { scan-assembler-times {fmov\ts} 1 {target lp64} } } */
> +/* { dg-final { scan-assembler-times {fmov\td} 2 {target lp64} } } */
> +/* { dg-final { scan-assembler-times {fmov\ts} 2 {target ilp32} } } */
> +/* { dg-final { scan-assembler-times {fmov\td} 1 {target ilp32} } } */
> +/* { dg-final { scan-assembler-times {ldr\ts} 1 } } */
