[Bug target/105981] [10/11/12 regression] Wrong code from gen_cpymem_ldrd_strd() with -mbig-endian
cvs-commit at gcc dot gnu.org
Thu Jun 16 12:46:58 GMT 2022
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Richard Earnshaw
Author: Richard Earnshaw <firstname.lastname@example.org>
Date: Wed Jun 15 16:07:20 2022 +0100
arm: big-endian issue in gen_cpymem_ldrd_strd [PR105981]
The code in gen_cpymem_ldrd_strd has been incorrect for big-endian
since r230663. The problem is that we use gen_lowpart, etc. to split
the 64-bit quantity, but fail to account for the fact that these
routines are really dealing with 64-bit /values/ and in big-endian the
ordering of the sub-registers changes.
To fix this, I've renamed the conceptually misnamed low_reg and hi_reg
as first_reg and second_reg, and then used different logic for
big-endian targets to initialize these values. This makes the logic
clearer than trying to think about high bits and low bits.
* config/arm/arm.c (gen_cpymem_ldrd_strd): Rename low_reg and
to first_reg and second_reg respectively. Initialize them
when generating big-endian code.
(cherry picked from commit 8aaa948059a8b5f0a62ad010d0aa6346b7ac9cd3)
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