[r16-5879 Regression] FAIL: gcc.dg/asm-hard-reg-9.c (test for excess errors) on Linux/x86_64

[Haochen Jiang]

On Linux/x86_64,

55cc4377a310f00b0790eb2ab218fe130f63a408 is the first bad commit
commit 55cc4377a310f00b0790eb2ab218fe130f63a408
Author: Stefan Schulze Frielinghaus <stefansf@gcc.gnu.org>
Date:   Thu Dec 4 09:36:24 2025 +0100

    lra: Honor exclude start regs while reusing reloads

caused

FAIL: gcc.dg/asm-hard-reg-9.c (test for excess errors)

with GCC configured with

../../gcc/configure --prefix=/export/users3/haochenj/src/gcc-bisect/master/master/r16-5879/usr --enable-clocale=gnu --with-system-zlib --with-demangler-in-ld --with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl --enable-libmpx x86_64-linux --disable-bootstrap

To reproduce:

$ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gcc.dg/asm-hard-reg-9.c --target_board='unix{-m32}'"
$ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gcc.dg/asm-hard-reg-9.c --target_board='unix{-m32\ -march=cascadelake}'"

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