[PATCH] Don't expand *MEM_REF using extract_bit_field or movmisalign for EXPAND_MEMORY (PR inline-asm/56405)

Richard Biener rguenther@suse.de
Thu Feb 21 09:07:00 GMT 2013


On Thu, 21 Feb 2013, Jakub Jelinek wrote:

> Hi!
> 
> If an input operand of inline-asm doesn't allow registers, but allows
> memory, we expand it with EXPAND_MEMORY modifier (the only case of using
> that modifier).  But the movmisalign code added for 4.6 and especially
> the extract_bit_field code added for 4.8 results in getting a REG from
> expand_expr called with a *MEM_REF with EXPAND_MEMORY, instead of MEM the
> caller expects and can only handle, therefore we ICE.
> 
> This patch fixes it by honoring EXPAND_MEMORY in these cases, it is the sole
> responsibility of the inline asm writer to do the right thing in there for
> misaligned mems (e.g. gcc could pessimistically expect it might be
> misaligned, but user knows it will not).
> 
> Bootstrapped/regtested on {x86_64,i686,armv7hl,ppc,ppc64,s390,s390x}-linux,
> ok for trunk?

Ok.

Thanks,
Richard.

> 2013-02-21  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR inline-asm/56405
> 	* expr.c (expand_expr_real_1) <case TARGET_MEM_REF, MEM_REF>: Don't
> 	use movmisalign or extract_bit_field for EXPAND_MEMORY modifier.
> 
> 	* gcc.c-torture/compile/pr56405.c: New test.
> 
> --- gcc/expr.c.jj	2013-01-18 18:09:40.000000000 +0100
> +++ gcc/expr.c	2013-02-20 10:29:34.513143634 +0100
> @@ -9551,6 +9551,7 @@ expand_expr_real_1 (tree exp, rtx target
>  	set_mem_addr_space (temp, as);
>  	align = get_object_alignment (exp);
>  	if (modifier != EXPAND_WRITE
> +	    && modifier != EXPAND_MEMORY
>  	    && mode != BLKmode
>  	    && align < GET_MODE_ALIGNMENT (mode)
>  	    /* If the target does not have special handling for unaligned
> @@ -9639,6 +9640,7 @@ expand_expr_real_1 (tree exp, rtx target
>  	if (TREE_THIS_VOLATILE (exp))
>  	  MEM_VOLATILE_P (temp) = 1;
>  	if (modifier != EXPAND_WRITE
> +	    && modifier != EXPAND_MEMORY
>  	    && mode != BLKmode
>  	    && align < GET_MODE_ALIGNMENT (mode))
>  	  {
> --- gcc/testsuite/gcc.c-torture/compile/pr56405.c.jj	2013-02-20 10:32:17.807250979 +0100
> +++ gcc/testsuite/gcc.c-torture/compile/pr56405.c	2013-02-20 10:32:46.963090873 +0100
> @@ -0,0 +1,7 @@
> +/* PR inline-asm/56405 */
> +
> +void
> +foo (void)
> +{
> +  asm volatile ("" : "+m" (*(volatile unsigned short *) 0x1001UL));
> +}
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend



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