diff mbox series

Fix HWI + -unsigned in combine.c

Message ID 87tvyrym94.fsf@linaro.org
State New
Headers show
Series Fix HWI + -unsigned in combine.c | expand

Commit Message

Richard Sandiford Oct. 22, 2017, 8:13 p.m. UTC 
rtx_equal_for_field_assignment_p had:

 	x = adjust_address_nv (x, GET_MODE (y),
			       -subreg_lowpart_offset (GET_MODE (x),
						       GET_MODE (y)));

But subreg_lowpart_offset returns an unsigned int and
adjust_address_nv takes a HWI, so a subreg offset of 4 would
give a memory offset of 0x00000000fffffffffc.

The SVE series makes this go away by using HWI-based types for
both interfaces, but in this case the fix is also a minor clean-up.

Tested on aarch64-linux-gnu, powerpc64le-linux-gnu and
x86_64-linux-gnu.  OK to install?

Richard


2017-10-22  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* combine.c (rtx_equal_for_field_assignment_p): Use
	byte_lowpart_offset.

Comments

Segher Boessenkool Oct. 22, 2017, 11:18 p.m. UTC | #1 
Hi!

On Sun, Oct 22, 2017 at 09:13:11PM +0100, Richard Sandiford wrote:
> rtx_equal_for_field_assignment_p had:

> 

>  	x = adjust_address_nv (x, GET_MODE (y),

> 			       -subreg_lowpart_offset (GET_MODE (x),

> 						       GET_MODE (y)));

> 

> But subreg_lowpart_offset returns an unsigned int and

> adjust_address_nv takes a HWI, so a subreg offset of 4 would

> give a memory offset of 0x00000000fffffffffc.

> 

> The SVE series makes this go away by using HWI-based types for

> both interfaces, but in this case the fix is also a minor clean-up.

> 

> Tested on aarch64-linux-gnu, powerpc64le-linux-gnu and

> x86_64-linux-gnu.  OK to install?


Yes please, thanks!


Segher


> 2017-10-22  Richard Sandiford  <richard.sandiford@linaro.org>

> 

> gcc/

> 	* combine.c (rtx_equal_for_field_assignment_p): Use

> 	byte_lowpart_offset.

> 

> Index: gcc/combine.c

> ===================================================================

> --- gcc/combine.c	2017-10-22 21:04:50.138830154 +0100

> +++ gcc/combine.c	2017-10-22 21:04:59.000825360 +0100

> @@ -9526,13 +9526,9 @@ rtx_equal_for_field_assignment_p (rtx x,

>  	return 0;

>        if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN)

>  	return 0;

> -      /* For big endian, adjust the memory offset.  */

> -      if (BYTES_BIG_ENDIAN)

> -	x = adjust_address_nv (x, GET_MODE (y),

> -			       -subreg_lowpart_offset (GET_MODE (x),

> -						       GET_MODE (y)));

> -      else

> -	x = adjust_address_nv (x, GET_MODE (y), 0);

> +      x = adjust_address_nv (x, GET_MODE (y),

> +			     byte_lowpart_offset (GET_MODE (y),

> +						  GET_MODE (x)));

>      }

>  

>    if (x == y || rtx_equal_p (x, y))
diff mbox series

Patch

Index: gcc/combine.c
===================================================================
--- gcc/combine.c	2017-10-22 21:04:50.138830154 +0100
+++ gcc/combine.c	2017-10-22 21:04:59.000825360 +0100
@@ -9526,13 +9526,9 @@  rtx_equal_for_field_assignment_p (rtx x,
 	return 0;
       if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN)
 	return 0;
-      /* For big endian, adjust the memory offset.  */
-      if (BYTES_BIG_ENDIAN)
-	x = adjust_address_nv (x, GET_MODE (y),
-			       -subreg_lowpart_offset (GET_MODE (x),
-						       GET_MODE (y)));
-      else
-	x = adjust_address_nv (x, GET_MODE (y), 0);
+      x = adjust_address_nv (x, GET_MODE (y),
+			     byte_lowpart_offset (GET_MODE (y),
+						  GET_MODE (x)));
     }
 
   if (x == y || rtx_equal_p (x, y))