[llvm] [RISCV] Handled the uimm9 offset while FrameIndex folding. (PR #149303)

[via llvm-commits]

ukalappa-mips wrote:

@topperc  ,we traced out the PrologEpilogInsterter with gdb  like 

(gdb) p MI.dump()
  MIPS_PREFETCH %stack.0.data, 508, 8 :: (non-temporal "riscv-nontemporal-domain-bit-0" "riscv-nontemporal-domain-bit-1" load (s8) from %ir.ptr)
$1 = void
(gdb) n
578         if (Opc == RISCV::ADDI && !isInt<12>(Val)) {
(gdb) n
585         } else if ((Opc == RISCV::PREFETCH_I || Opc == RISCV::PREFETCH_R ||
(gdb) n
590         } else if (Opc == RISCV::MIPS_PREFETCH && !isUInt<9>(Val)) {
(gdb) s

(gdb) bt
#0  llvm::MachineOperand::ChangeToImmediate (this=0x5555556a2748, ImmVal=0, TargetFlags=0) at llvm-project/llvm/lib/CodeGen/MachineOperand.cpp:162
#1  0x00007ffff76a94fa in llvm::RISCVRegisterInfo::eliminateFrameIndex (this=0x7fffef613338, II=..., SPAdj=0, FIOperandNum=0, RS=0x0) at /llvm-project/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp:593
#2  0x00007ffff4bcef09 in (anonymous namespace)::PEIImpl::replaceFrameIndicesBackward (this=0x7fffffffd200, BB=0x5555556a2570, MF=..., SPAdj=@0x7fffffffce7c: 0) at/llvm-project/llvm/lib/CodeGen/PrologEpilogInserter.cpp:1502
#3  0x00007ffff4bce351 in (anonymous namespace)::PEIImpl::replaceFrameIndicesBackward (this=0x7fffffffd200, MF=...) at /llvm-project/llvm/lib/CodeGen/PrologEpilogInserter.cpp:1359
#4  0x00007ffff4bc8b7f in (anonymous namespace)::PEIImpl::run (this=0x7fffffffd200, MF=...) at /llvm-project/llvm/lib/CodeGen/PrologEpilogInserter.cpp:284

here the offset "Val" is 508 ,which triggers the changes and fold the offset with ADDI.

https://github.com/llvm/llvm-project/pull/149303