Emit CFI to FP but don't move FP

Author: lenary

llvm/lib/Target/RISCV/RISCVFrameLowering.cpp

@@ -974,17 +974,20 @@ void RISCVFrameLowering::emitPrologue(MachineFunction &MF,
   emitCFIForCSI<CFISaveRegisterEmitter>(MBB, MBBI, getUnmanagedCSI(MF, CSI));
 
   // Generate new FP.
-  if (hasFP(MF) && RVFI->getPushPopKind(MF) !=
-                       RISCVMachineFunctionInfo::PushPopKind::VendorXqccmp) {
+  if (hasFP(MF)) {
     if (STI.isRegisterReservedByUser(FPReg))
       MF.getFunction().getContext().diagnose(DiagnosticInfoUnsupported{
           MF.getFunction(), "Frame pointer required, but has been reserved."});
     // The frame pointer does need to be reserved from register allocation.
     assert(MF.getRegInfo().isReserved(FPReg) && "FP not reserved");
 
-    RI->adjustReg(MBB, MBBI, DL, FPReg, SPReg,
-                  StackOffset::getFixed(RealStackSize - RVFI->getVarArgsSaveSize()),
-                  MachineInstr::FrameSetup, getStackAlign());
+    // Xqxxmp with hasFP will update FP using `qc.cm.pushfp`, so we don't need
+    // to update it again, but we do need to emit the `.cfi_def_cfa` below.
+    if (RVFI->getPushPopKind(MF) != RISCVMachineFunctionInfo::PushPopKind::VendorXqccmp) {
+      RI->adjustReg(MBB, MBBI, DL, FPReg, SPReg,
+                    StackOffset::getFixed(RealStackSize - RVFI->getVarArgsSaveSize()),
+                    MachineInstr::FrameSetup, getStackAlign());
+    }
 
     // Emit ".cfi_def_cfa $fp, RVFI->getVarArgsSaveSize()"
     unsigned CFIIndex = MF.addFrameInst(MCCFIInstruction::cfiDefCfa(

llvm/test/CodeGen/RISCV/xqccmp-callee-saved-gprs.ll

@@ -128,6 +128,7 @@ define void @callee() {
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset s9, -44
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset s10, -48
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset s11, -52
+; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa s0, 0
 ; RV32IXQCCMP-WITH-FP-NEXT:    lui t1, %hi(var)
 ; RV32IXQCCMP-WITH-FP-NEXT:    lw a0, %lo(var)(t1)
 ; RV32IXQCCMP-WITH-FP-NEXT:    sw a0, -56(s0) # 4-byte Folded Spill
@@ -325,6 +326,7 @@ define void @callee() {
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset s9, -88
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset s10, -96
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset s11, -104
+; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa s0, 0
 ; RV64IXQCCMP-WITH-FP-NEXT:    lui t1, %hi(var)
 ; RV64IXQCCMP-WITH-FP-NEXT:    lw a0, %lo(var)(t1)
 ; RV64IXQCCMP-WITH-FP-NEXT:    sd a0, -112(s0) # 8-byte Folded Spill
@@ -569,6 +571,7 @@ define void @caller() {
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset s11, -52
 ; RV32IXQCCMP-WITH-FP-NEXT:    addi sp, sp, -32
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa_offset 144
+; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa s0, 0
 ; RV32IXQCCMP-WITH-FP-NEXT:    lui s6, %hi(var)
 ; RV32IXQCCMP-WITH-FP-NEXT:    lw a0, %lo(var)(s6)
 ; RV32IXQCCMP-WITH-FP-NEXT:    sw a0, -56(s0) # 4-byte Folded Spill
@@ -840,6 +843,7 @@ define void @caller() {
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset s11, -104
 ; RV64IXQCCMP-WITH-FP-NEXT:    addi sp, sp, -128
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa_offset 288
+; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa s0, 0
 ; RV64IXQCCMP-WITH-FP-NEXT:    lui s6, %hi(var)
 ; RV64IXQCCMP-WITH-FP-NEXT:    lw a0, %lo(var)(s6)
 ; RV64IXQCCMP-WITH-FP-NEXT:    sd a0, -112(s0) # 8-byte Folded Spill
@@ -983,6 +987,7 @@ define void @foo() {
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset ra, -4
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset s0, -8
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset s4, -24
+; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa s0, 0
 ; RV32IXQCCMP-WITH-FP-NEXT:    #APP
 ; RV32IXQCCMP-WITH-FP-NEXT:    li s4, 0
 ; RV32IXQCCMP-WITH-FP-NEXT:    #NO_APP
@@ -1006,6 +1011,7 @@ define void @foo() {
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset ra, -8
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset s0, -16
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset s4, -48
+; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa s0, 0
 ; RV64IXQCCMP-WITH-FP-NEXT:    #APP
 ; RV64IXQCCMP-WITH-FP-NEXT:    li s4, 0
 ; RV64IXQCCMP-WITH-FP-NEXT:    #NO_APP
@@ -1035,6 +1041,7 @@ define void @bar() {
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset ra, -4
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset s0, -8
 ; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_offset s11, -52
+; RV32IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa s0, 0
 ; RV32IXQCCMP-WITH-FP-NEXT:    #APP
 ; RV32IXQCCMP-WITH-FP-NEXT:    li s11, 0
 ; RV32IXQCCMP-WITH-FP-NEXT:    #NO_APP
@@ -1058,6 +1065,7 @@ define void @bar() {
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset ra, -8
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset s0, -16
 ; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_offset s11, -104
+; RV64IXQCCMP-WITH-FP-NEXT:    .cfi_def_cfa s0, 0
 ; RV64IXQCCMP-WITH-FP-NEXT:    #APP
 ; RV64IXQCCMP-WITH-FP-NEXT:    li s11, 0
 ; RV64IXQCCMP-WITH-FP-NEXT:    #NO_APP