Skip to content

[RISCV] Handle 'c.addi x0, $imm' alias for c.nop using PseudoC_ADDI_NOP. #150719

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Jul 26, 2025
Merged

[RISCV] Handle 'c.addi x0, $imm' alias for c.nop using PseudoC_ADDI_NOP. #150719

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
49b40e6
[RISCV] Handle 'c.addi x0, $imm' alias for c.nop using PseudoC_ADDI_NOP.
topperc Jul 25, 2025
778e761
fixup! clang-format
topperc Jul 26, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 7 additions & 2 deletions llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3849,9 +3849,14 @@ bool RISCVAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
switch (Inst.getOpcode()) {
default:
break;
case RISCV::PseudoC_ADDI_NOP:
emitToStreamer(Out, MCInstBuilder(RISCV::C_NOP));
case RISCV::PseudoC_ADDI_NOP: {
if (Inst.getOperand(2).getImm() == 0)
emitToStreamer(Out, MCInstBuilder(RISCV::C_NOP));
else
emitToStreamer(Out, MCInstBuilder(RISCV::C_NOP_HINT)
.addOperand(Inst.getOperand(2)));
return false;
}
case RISCV::PseudoLLAImm:
case RISCV::PseudoLAImm:
case RISCV::PseudoLI: {
Expand Down
13 changes: 5 additions & 8 deletions llvm/lib/Target/RISCV/RISCVInstrInfoC.td
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -408,11 +408,13 @@ def C_ADDI : RVInst16CI<0b000, 0b01, (outs GPRNoX0:$rd_wb),
let Constraints = "$rd = $rd_wb";
}

// Alternate syntax for c.nop. Converted to C_NOP by the assembler.
// Alternate syntax for c.nop. Converted to C_NOP/C_NOP_HINT by the assembler.
let hasSideEffects = 0, mayLoad = 0, mayStore = 0, isCodeGenOnly = 0,
isAsmParserOnly = 1 in
def PseudoC_ADDI_NOP : Pseudo<(outs GPRX0:$rd), (ins GPRX0:$rs1, immzero:$imm),
[], "c.addi", "$rd, $imm">;
def PseudoC_ADDI_NOP : Pseudo<(outs GPRX0:$rd), (ins GPRX0:$rs1, simm6:$imm),
[], "c.addi", "$rd, $imm"> {
let Constraints = "$rs1 = $rd";
}

let hasSideEffects = 0, mayLoad = 0, mayStore = 0, isCall = 1,
DecoderNamespace = "RV32Only", Defs = [X1],
Expand Down Expand Up @@ -698,11 +700,6 @@ def C_SRAI64_HINT : RVInst16CB<0b100, 0b01, (outs GPRC:$rd),
// Assembler Pseudo Instructions
//===----------------------------------------------------------------------===//

let Predicates = [HasStdExtZca] in {
// Just a different syntax for the c.nop hint: c.addi x0, simm6 vs c.nop simm6.
def : InstAlias<"c.addi x0, $imm", (C_NOP_HINT simm6nonzero:$imm), 0>;
}

let Predicates = [HasStdExtC, HasStdExtZihintntl] in {
def : InstAlias<"c.ntl.p1", (C_ADD_HINT X0, X2)>;
def : InstAlias<"c.ntl.pall", (C_ADD_HINT X0, X3)>;
Expand Down
2 changes: 1 addition & 1 deletion llvm/test/MC/RISCV/rvc-hints-invalid.s
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@

c.nop 0 # CHECK: :[[@LINE]]:7: error: immediate must be non-zero in the range [-32, 31]

c.addi x0, 33 # CHECK: :[[@LINE]]:12: error: immediate must be non-zero in the range [-32, 31]
c.addi x0, 33 # CHECK: :[[@LINE]]:12: error: immediate must be an integer in the range [-32, 31]

c.li x0, 42 # CHECK: :[[@LINE]]:10: error: immediate must be an integer in the range [-32, 31]

Expand Down
Loading