diff --git a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp --- a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp +++ b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp @@ -107,8 +107,6 @@ void RISCVFrameLowering::emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const { - assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported"); - MachineFrameInfo &MFI = MF.getFrameInfo(); auto *RVFI = MF.getInfo(); const RISCVRegisterInfo *RI = STI.getRegisterInfo(); @@ -246,14 +244,28 @@ void RISCVFrameLowering::emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const { - MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr(); const RISCVRegisterInfo *RI = STI.getRegisterInfo(); MachineFrameInfo &MFI = MF.getFrameInfo(); auto *RVFI = MF.getInfo(); - DebugLoc DL = MBBI->getDebugLoc(); Register FPReg = getFPReg(STI); Register SPReg = getSPReg(STI); + // Get the insert location for the epilogue. If there were no terminators in + // the block, get the last instruction. + MachineBasicBlock::iterator MBBI = MBB.end(); + DebugLoc DL; + if (!MBB.empty()) { + MBBI = MBB.getFirstTerminator(); + if (MBBI == MBB.end()) + MBBI = MBB.getLastNonDebugInstr(); + DL = MBBI->getDebugLoc(); + + // If this is not a terminator, the actual insert location should be after the + // last instruction. + if (!MBBI->isTerminator()) + MBBI = std::next(MBBI); + } + // Skip to before the restores of callee-saved registers // FIXME: assumes exactly one instruction is used to restore each // callee-saved register. diff --git a/llvm/test/CodeGen/RISCV/shrinkwrap.ll b/llvm/test/CodeGen/RISCV/shrinkwrap.ll new file mode 100644 --- /dev/null +++ b/llvm/test/CodeGen/RISCV/shrinkwrap.ll @@ -0,0 +1,97 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py +; RUN: llc -mtriple riscv32 < %s | FileCheck %s -check-prefix=RV32I-NOSW +; RUN: llc -mtriple riscv32 -enable-shrink-wrap < %s | FileCheck %s -check-prefix=RV32I-SW + + +declare void @abort() + +define void @eliminate_restore(i32 %n) nounwind { +; RV32I-NOSW-LABEL: eliminate_restore: +; RV32I-NOSW: # %bb.0: +; RV32I-NOSW-NEXT: addi sp, sp, -16 +; RV32I-NOSW-NEXT: sw ra, 12(sp) +; RV32I-NOSW-NEXT: addi a1, zero, 32 +; RV32I-NOSW-NEXT: bgeu a1, a0, .LBB0_2 +; RV32I-NOSW-NEXT: # %bb.1: # %if.end +; RV32I-NOSW-NEXT: lw ra, 12(sp) +; RV32I-NOSW-NEXT: addi sp, sp, 16 +; RV32I-NOSW-NEXT: ret +; RV32I-NOSW-NEXT: .LBB0_2: # %if.then +; RV32I-NOSW-NEXT: call abort +; +; RV32I-SW-LABEL: eliminate_restore: +; RV32I-SW: # %bb.0: +; RV32I-SW-NEXT: addi a1, zero, 32 +; RV32I-SW-NEXT: bgeu a1, a0, .LBB0_2 +; RV32I-SW-NEXT: # %bb.1: # %if.end +; RV32I-SW-NEXT: ret +; RV32I-SW-NEXT: .LBB0_2: # %if.then +; RV32I-SW-NEXT: addi sp, sp, -16 +; RV32I-SW-NEXT: sw ra, 12(sp) +; RV32I-SW-NEXT: call abort + %cmp = icmp ule i32 %n, 32 + br i1 %cmp, label %if.then, label %if.end + +if.then: + call void @abort() + unreachable + +if.end: + ret void +} + +declare void @notdead(i8*) + +define void @conditional_alloca(i32 %n) nounwind { +; RV32I-NOSW-LABEL: conditional_alloca: +; RV32I-NOSW: # %bb.0: +; RV32I-NOSW-NEXT: addi sp, sp, -16 +; RV32I-NOSW-NEXT: sw ra, 12(sp) +; RV32I-NOSW-NEXT: sw s0, 8(sp) +; RV32I-NOSW-NEXT: addi s0, sp, 16 +; RV32I-NOSW-NEXT: addi a1, zero, 32 +; RV32I-NOSW-NEXT: bltu a1, a0, .LBB1_2 +; RV32I-NOSW-NEXT: # %bb.1: # %if.then +; RV32I-NOSW-NEXT: addi a0, a0, 15 +; RV32I-NOSW-NEXT: andi a0, a0, -16 +; RV32I-NOSW-NEXT: sub a0, sp, a0 +; RV32I-NOSW-NEXT: mv sp, a0 +; RV32I-NOSW-NEXT: call notdead +; RV32I-NOSW-NEXT: .LBB1_2: # %if.end +; RV32I-NOSW-NEXT: addi sp, s0, -16 +; RV32I-NOSW-NEXT: lw s0, 8(sp) +; RV32I-NOSW-NEXT: lw ra, 12(sp) +; RV32I-NOSW-NEXT: addi sp, sp, 16 +; RV32I-NOSW-NEXT: ret +; +; RV32I-SW-LABEL: conditional_alloca: +; RV32I-SW: # %bb.0: +; RV32I-SW-NEXT: addi a1, zero, 32 +; RV32I-SW-NEXT: bltu a1, a0, .LBB1_2 +; RV32I-SW-NEXT: # %bb.1: # %if.then +; RV32I-SW-NEXT: addi sp, sp, -16 +; RV32I-SW-NEXT: sw ra, 12(sp) +; RV32I-SW-NEXT: sw s0, 8(sp) +; RV32I-SW-NEXT: addi s0, sp, 16 +; RV32I-SW-NEXT: addi a0, a0, 15 +; RV32I-SW-NEXT: andi a0, a0, -16 +; RV32I-SW-NEXT: sub a0, sp, a0 +; RV32I-SW-NEXT: mv sp, a0 +; RV32I-SW-NEXT: call notdead +; RV32I-SW-NEXT: addi sp, s0, -16 +; RV32I-SW-NEXT: lw s0, 8(sp) +; RV32I-SW-NEXT: lw ra, 12(sp) +; RV32I-SW-NEXT: addi sp, sp, 16 +; RV32I-SW-NEXT: .LBB1_2: # %if.end +; RV32I-SW-NEXT: ret + %cmp = icmp ule i32 %n, 32 + br i1 %cmp, label %if.then, label %if.end + +if.then: + %addr = alloca i8, i32 %n + call void @notdead(i8* %addr) + br label %if.end + +if.end: + ret void +}