[RISCV] Add Zilsd to RISCVMergeBaseOffset. (#140157)

I only tested a simple case for folding the addi from medany codemodel.
I assume everything else should just work.

Author: topperc

llvm/lib/Target/RISCV/RISCVMergeBaseOffset.cpp

@@ -409,6 +409,7 @@ bool RISCVMergeBaseOffsetOpt::foldIntoMemoryOps(MachineInstr &Hi,
     case RISCV::LHU:
     case RISCV::LWU:
     case RISCV::LD:
+    case RISCV::LD_RV32:
     case RISCV::FLH:
     case RISCV::FLW:
     case RISCV::FLD:
@@ -418,6 +419,7 @@ bool RISCVMergeBaseOffsetOpt::foldIntoMemoryOps(MachineInstr &Hi,
     case RISCV::SW:
     case RISCV::SW_INX:
     case RISCV::SD:
+    case RISCV::SD_RV32:
     case RISCV::FSH:
     case RISCV::FSW:
     case RISCV::FSD: {

llvm/test/CodeGen/RISCV/fold-addi-loadstore-zilsd.ll

@@ -0,0 +1,30 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -mattr=+zdinx,+zilsd -verify-machineinstrs \
+; RUN:   -code-model=medium < %s | FileCheck %s
+
+@g_0 = global double 0.0
+
+define double @load_g_0() nounwind {
+; CHECK-LABEL: load_g_0:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:  .Lpcrel_hi0:
+; CHECK-NEXT:    auipc a0, %pcrel_hi(g_0)
+; CHECK-NEXT:    ld a0, %pcrel_lo(.Lpcrel_hi0)(a0)
+; CHECK-NEXT:    ret
+entry:
+  %0 = load double, ptr @g_0
+  ret double %0
+}
+
+define void @store_g_0() nounwind {
+; CHECK-LABEL: store_g_0:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:  .Lpcrel_hi1:
+; CHECK-NEXT:    auipc a0, %pcrel_hi(g_0)
+; CHECK-NEXT:    fcvt.d.w a2, zero
+; CHECK-NEXT:    sd a2, %pcrel_lo(.Lpcrel_hi1)(a0)
+; CHECK-NEXT:    ret
+entry:
+  store double 0.0, ptr @g_0
+  ret void
+}