[PATCH v1 0/1] Fix the VSTART register was not checked correctly in the vext_vv_rm_2 function

[Chao Liu]

Hi, all:

Recently, when I was writing a RISCV test, I found that when VL is set to 0, the
instruction should be nop, but when I tested it, I found that QEMU will treat
all elements as tail elements, and in the case of VTA=1, write all elements
to 1.

After troubleshooting, it was found that the vext_vx_rm_1 function was called in
the vext_vx_rm_2, and then the vext_set_elems_1s function was called to process
the tail element, but only VSTART >= vl was checked in the vext_vx_rm_1
function, which caused the tail element to still be processed even if it was
returned in advance.

So I've made the following change:

put VSTART_CHECK_EARLY_EXIT(env) at the beginning of the vext_vx_rm_2 function,
so that the VSTART register is checked correctly.

Regards,
Chao

Chao Liu (1):
  target/riscv: Fix handling of NOP for vstart >= vl in vext_vx_rm_2()

 target/riscv/vector_helper.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

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2.47.1