Clang compile issue for branch instructions

[kumaransvyoma]

Branch instruction compiles inversely

• When beq is complied with an offset using clang ,it compiles as bne, and vice-versa.
• Similarly, for other branch instructions(('blt', 'bltu', 'bge', 'bge', 'bgeu').
• sample setup -branch.zip

  
  # sample test
  "
  check:
  lui s0,0xfffff
  add s0,s0,-1 
  lui tp,0x20
  beq s0,tp, ret           
  beq s0,tp, ret+0      //compiles as bne *
  ret:
  add a1,a1,3
  "

compiled as

" 80000120: fffff437 lui s0,0xfffff 80000124: fff40413 add s0,s0,-1 # ffffefff <immx+0x452f152f> 80000128: 00020237 lui tp,0x20 8000012c: 00440663 beq s0,tp,80000138 80000130: 00441463 bne s0,tp,80000138 80000134: 0040006f j 80000138 "

## To reproduce the issue

to compile

clang -march=rv32i -static -mcmodel=medany -fvisibility=hidden -nostdlib -nostartfiles -T ./env/link.ld -I ./env -mabi=ilp32 ./beq.S -o dut.elf -DTEST_CASE_1=True -DXLEN=32

to see disassembly file

riscv32-unknown-elf-objdump -d dut.elf > dut.disass

[lavanyajagan]

fixed with version 18 release