[PATCH][AArch64] Fix ICE on (const_double:HF 0.0)

[Alan Lawrence]

On 26/10/15 16:26, Alan Lawrence wrote:
> The included testcase demonstrates the ICE: aarch64_valid_floating_const
> (via aarch64_float_const_representable_p) disables HFmode immediates, but
> allows 0.0. However, *movhf_aarch64 does not allow this insn:
>
> (insn 7 6 10 2 (set (mem:HF (reg/f:DI 73) [0 *f_2(D)+0 S2 A16])
>          (const_double:HF 0.0 [0x0.0p+0])) test.c:8 -1
>       (nil))
>
> Fix is to allow the second operand to be zero, in the same way as
> *movsf_aarch64.
>
> Bootstrapped + check-gcc on aarch64-none-linux-gnu.
> New test also passing on arm-none-eabi.
>
> OK for trunk?
>
> gcc/ChangeLog:
>
> 	* config/aarch64/aarch64.md (*movhf_aarch64): Use
> 	aarch64_reg_or_fp_zero for second operand.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/aarch64/fp16/set_zero_1.c: New.
> ---
>   gcc/config/aarch64/aarch64.md                      |  2 +-
>   gcc/testsuite/gcc.target/aarch64/fp16/set_zero_1.c | 22 ++++++++++++++++++++++
>   2 files changed, 23 insertions(+), 1 deletion(-)
>   create mode 100644 gcc/testsuite/gcc.target/aarch64/fp16/set_zero_1.c
>
> diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
> index 78b9ae2..8895a4e 100644
> --- a/gcc/config/aarch64/aarch64.md
> +++ b/gcc/config/aarch64/aarch64.md
> @@ -1120,7 +1120,7 @@
>     [(set (match_operand:HF 0 "nonimmediate_operand" "=w, ?r,w,w,m,r,m ,r")
>   	(match_operand:HF 1 "general_operand"      "?rY, w,w,m,w,m,rY,r"))]
>     "TARGET_FLOAT && (register_operand (operands[0], HFmode)
> -    || register_operand (operands[1], HFmode))"
> +    || aarch64_reg_or_fp_zero (operands[1], HFmode))"
>     "@
>      mov\\t%0.h[0], %w1
>      umov\\t%w0, %1.h[0]
> diff --git a/gcc/testsuite/gcc.target/aarch64/fp16/set_zero_1.c b/gcc/testsuite/gcc.target/aarch64/fp16/set_zero_1.c
> new file mode 100644
> index 0000000..36cadfd
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/fp16/set_zero_1.c
> @@ -0,0 +1,22 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2" } */
> +/* { dg-additional-options "-mfp16-format=ieee" { target "arm*-*-*" } } */
> +
> +extern void abort (void);
> +
> +__attribute__ ((noinline))
> +void
> +setfoo (__fp16 *f)
> +{
> +  *f = 0.0;
> +}
> +
> +int
> +main (int argc, char **argv)
> +{
> +  __fp16 a = 1.0;
> +  setfoo (&a);
> +  if (a != 0.0)
> +    abort ();
> +  return 0;
> +}
>

Ping.

--Alan