Re: [PATCH] simplify-rtx: Fix VOIDmode operand handling in simplify_subreg [PR108805]

[Richard Biener <rguenther@suse.de>]

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On Thu, 16 Feb 2023, Uros Bizjak wrote:

> simplify_subreg can return VOIDmode const_int operand and will
> cause ICE in simplify_gen_subreg when this operand is passed to it.
> 
> The patch prevents VOIDmode temporary from entering simplify_gen_subreg.
> We can't process const_int operand any further, since outermode
> is not an integer mode here.

But if it's a CONST_INT then we know it's of int_outermode, no? That is,
doesn't simplify_subreg (mode, ...) always return something in 'mode'
and thus we can always pass just 'mode' as third argument to the
following simplify_gen_subreg call?

Richard.

> 2023-02-16  Uroš Bizjak  <ubizjak@gmail.com>
> 
> gcc/ChangeLog:
> 
>     PR target/108805
>     * simplify_rtx.cc (simplify_context::simplify_subreg): Prevent
>     VOIDmode const_int result from simplify_subreg from entering
>     simplify_gen_subreg.
> 
> gcc/testsuite/ChangeLog:
> 
>     PR target/108805
>     * gcc.dg/pr108805.c: New test.
> 
> Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
> 
> OK for master and release branches?
> 
> Uros.
> 

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