On Tue, 3 Mar 2020, Jakub Jelinek wrote:
> Hi!
>
> The following testcase ICEs in cross to riscv64-linux. The problem is
> that we have a DImode integral constant (that doesn't fit into SImode),
> which is pushed into a constant pool and later access just the first half of
> it using a MEM. When plus_constant is called on such a MEM, if the constant
> has mode, we verify the mode, but if it doesn't, we don't and ICE later on
> when we think the CONST_INT is a valid SImode constant.
>
> Fixed thusly, tested with cross to riscv64-linux and bootstrapped/regtested
> on x86_64-linux and i686-linux, ok for trunk?
Looks OK, but I guess we could do better by appropriately sub-regging
the constant (which might not always be possible of course).
Thanks,
Richard.
> 2020-03-03 Jakub Jelinek <ja...@redhat.com>
>
> PR rtl-optimization/94002
> * explow.c (plus_constant): Punt if cst has VOIDmode and
> get_pool_mode is different from mode.
>
> * gcc.dg/pr94002.c: New test.
>
> --- gcc/explow.c.jj 2020-01-12 11:54:36.564411130 +0100
> +++ gcc/explow.c 2020-03-02 22:09:19.544380020 +0100
> @@ -128,6 +128,9 @@ plus_constant (machine_mode mode, rtx x,
> cst = gen_lowpart (mode, cst);
> gcc_assert (cst);
> }
> + else if (GET_MODE (cst) == VOIDmode
> + && get_pool_mode (XEXP (x, 0)) != mode)
> + break;
> if (GET_MODE (cst) == VOIDmode || GET_MODE (cst) == mode)
> {
> tem = plus_constant (mode, cst, c);
> --- gcc/testsuite/gcc.dg/pr94002.c.jj 2020-03-02 22:05:58.508338170 +0100
> +++ gcc/testsuite/gcc.dg/pr94002.c 2020-03-02 22:05:32.864715503 +0100
> @@ -0,0 +1,13 @@
> +/* PR rtl-optimization/94002 */
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fno-tree-dce -fno-tree-reassoc" } */
> +/* { dg-additional-options "-fPIC" { target fpic } } */
> +
> +unsigned a, b;
> +
> +void
> +foo (void)
> +{
> + __builtin_sub_overflow (b, 44852956282LL, &a);
> + a += ~b;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
