[Bug target/121449] New: [13/14/15/16 regression] Immediate offset out of range error for AArch64 SVE gather load

[Pengfei.Li2 at arm dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121449

            Bug ID: 121449
           Summary: [13/14/15/16 regression] Immediate offset out of range
                    error for AArch64 SVE gather load
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: Pengfei.Li2 at arm dot com
  Target Milestone: ---

Errors of “immediate offset out of range” are reported during assembly:

Assembler messages:
Error: immediate offset out of range 0 to 31 at operand 3 -- `ld1b
z1.d,p0/z,[z1.d,#56]'

To reproduce, point CC and CXX to a pre-built GCC trunk and do a bootstrap with
O3 and SVE enabled in stage1 flags on AArch64

$ export CC=/path/to/trunk/gcc CXX=/path/to/trunk/g++
$ /path/to/gcc/configure --enable-checking=release
$ make -j$(nproc) -l$(nproc) STAGE1_C{,XX}FLAGS="-O3 -march=armv8-a+sve"

I will upload a small reproducer.