[llvm] [RISCV][Zicfilp] Codegen LPAD insns by looking at module flags (PR #152121)

[Craig Topper via llvm-commits]

topperc wrote:

Do you plan to also address the code that uses `Subtarget.hasStdExtZicfilp()` in RISCVISelLowering and these patterns in RISCVInstrInfo.td

```
let Predicates = [NoStdExtZicfilp],                                              
    isBarrier = 1, isBranch = 1, isIndirectBranch = 1, isTerminator = 1 in       
def PseudoBRIND : Pseudo<(outs), (ins GPRJALR:$rs1, simm12:$imm12), []>,         
                  PseudoInstExpansion<(JALR X0, GPR:$rs1, simm12:$imm12)>;       
                                                                                 
let Predicates = [HasStdExtZicfilp],                                             
    isBarrier = 1, isBranch = 1, isIndirectBranch = 1, isTerminator = 1 in {     
def PseudoBRINDNonX7 : Pseudo<(outs), (ins GPRJALRNonX7:$rs1, simm12:$imm12), []>,
                       PseudoInstExpansion<(JALR X0, GPR:$rs1, simm12:$imm12)>;  
def PseudoBRINDX7 : Pseudo<(outs), (ins GPRX7:$rs1, simm12:$imm12), []>,         
                    PseudoInstExpansion<(JALR X0, GPR:$rs1, simm12:$imm12)>;     
}                                                                                
                                                                                 
// For Zicfilp, need to avoid using X7/T2 for indirect branches which need       
// landing pad.                                                                  
let Predicates = [HasStdExtZicfilp] in {                                         
def : Pat<(brind GPRJALRNonX7:$rs1), (PseudoBRINDNonX7 GPRJALRNonX7:$rs1, 0)>;   
def : Pat<(brind (add GPRJALRNonX7:$rs1, simm12:$imm12)),                        
          (PseudoBRINDNonX7 GPRJALRNonX7:$rs1, simm12:$imm12)>;                  
                                                                                 
def : Pat<(riscv_sw_guarded_brind GPRX7:$rs1), (PseudoBRINDX7 GPRX7:$rs1, 0)>;   
def : Pat<(riscv_sw_guarded_brind (add GPRX7:$rs1, simm12:$imm12)),              
          (PseudoBRINDX7 GPRX7:$rs1, simm12:$imm12)>;                            
}                                                                                
                                                                                 
let Predicates = [NoStdExtZicfilp] in {                                          
def : Pat<(brind GPRJALR:$rs1), (PseudoBRIND GPRJALR:$rs1, 0)>;                  
def : Pat<(brind (add GPRJALR:$rs1, simm12:$imm12)),                             
          (PseudoBRIND GPRJALR:$rs1, simm12:$imm12)>;                            
} 
```

https://github.com/llvm/llvm-project/pull/152121