Re: [PATCH, ARM] Fix ICE in arm_expand_neon_args

[Richard Earnshaw <rearnsha at arm dot com>]

On 07/01/14 15:09, Yufeng Zhang wrote:
> Hi,
> 
> The patch fixes an ICE in gcc/config/arm/arm.c:arm_expand_neon_args (). 
>   When the destination address for vst1q_lane_u64 is not aligned, 
> calling expand_normal will get a REG, which is not expected by 
> arm_expand_neon_args, resulting in an assertion failure.  Now, call 
> expand_expr with EXPAND_MEMORY to tell the expand that we really want a 
> MEM in the case of NEON_ARG_MEMORY.
> 
> OK for the trunk and 4.8 branch?
> 

OK for trunk.

Please let it gestate for 48 hours or so before backporting.

R.

> Thanks,
> Yufeng
> 
> gcc/
> 
> 	* config/arm/arm.c (arm_expand_neon_args): Call expand_expr
> 	with EXPAND_MEMORY for NEON_ARG_MEMORY; check if the returned
> 	rtx is const0_rtx or not.
> 
> gcc/testsuite/
> 
> 	* gcc.target/arm/neon/vst1Q_laneu64-1.c: New test.
> 
> 
> patch
> 
> 
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index 8fea2a6..a3b2796 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -24526,7 +24526,11 @@ arm_expand_neon_args (rtx target, int icode, int have_retval,
>  						    type_mode);
>              }
>  
> -          op[argc] = expand_normal (arg[argc]);
> +	  /* Use EXPAND_MEMORY for NEON_ARG_MEMORY to ensure a MEM_P
> +	     be returned.  */
> +	  op[argc] = expand_expr (arg[argc], NULL_RTX, VOIDmode,
> +				  (thisarg == NEON_ARG_MEMORY
> +				   ? EXPAND_MEMORY : EXPAND_NORMAL));
>  
>            switch (thisarg)
>              {
> @@ -24545,6 +24549,9 @@ arm_expand_neon_args (rtx target, int icode, int have_retval,
>                break;
>  
>              case NEON_ARG_MEMORY:
> +	      /* Check if expand failed.  */
> +	      if (op[argc] == const0_rtx)
> +		return 0;
>  	      gcc_assert (MEM_P (op[argc]));
>  	      PUT_MODE (op[argc], mode[argc]);
>  	      /* ??? arm_neon.h uses the same built-in functions for signed
> diff --git a/gcc/testsuite/gcc.target/arm/neon/vst1Q_laneu64-1.c b/gcc/testsuite/gcc.target/arm/neon/vst1Q_laneu64-1.c
> new file mode 100644
> index 0000000..5f4c927
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arm/neon/vst1Q_laneu64-1.c
> @@ -0,0 +1,25 @@
> +/* Test the `vst1Q_laneu64' ARM Neon intrinsic.  */
> +
> +/* Detect ICE in the case of unaligned memory address.  */
> +
> +/* { dg-do compile } */
> +/* { dg-require-effective-target arm_neon_ok } */
> +/* { dg-add-options arm_neon } */
> +
> +#include "arm_neon.h"
> +
> +unsigned char dummy_store[1000];
> +
> +void
> +foo (char* addr)
> +{
> +  uint8x16_t vdata = vld1q_u8 (addr);
> +  vst1q_lane_u64 ((uint64_t*) &dummy_store, vreinterpretq_u64_u8 (vdata), 0);
> +}
> +
> +uint64_t
> +bar (uint64x2_t vdata)
> +{
> +  vdata = vld1q_lane_u64 ((uint64_t*) &dummy_store, vdata, 0);
> +  return vgetq_lane_u64 (vdata, 0);
> +}
>