[llvm] Handle moves of non-16 size to/from CCR (PR #108581)

via llvm-commits llvm-commits at lists.llvm.org
Tue Oct 29 14:56:43 PDT 2024


https://github.com/knickish updated https://github.com/llvm/llvm-project/pull/108581

>From dce4c5757edfbcc990f4976ad71f3b038814f621 Mon Sep 17 00:00:00 2001
From: kirk <knickish at gmail.com>
Date: Fri, 13 Sep 2024 14:34:06 +0000
Subject: [PATCH 1/2] add pseudo instrs for 8 and 32 bit src/dst ccr moves and
 expand them to 16 bit instrs

---
 llvm/lib/Target/M68k/M68kExpandPseudo.cpp |  3 +++
 llvm/lib/Target/M68k/M68kInstrData.td     |  6 +++++
 llvm/lib/Target/M68k/M68kInstrInfo.cpp    | 27 ++++++++++++++++++-----
 3 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Target/M68k/M68kExpandPseudo.cpp b/llvm/lib/Target/M68k/M68kExpandPseudo.cpp
index c7fdd7d7c35023..e2e32a474cfd67 100644
--- a/llvm/lib/Target/M68k/M68kExpandPseudo.cpp
+++ b/llvm/lib/Target/M68k/M68kExpandPseudo.cpp
@@ -189,8 +189,11 @@ bool M68kExpandPseudo::ExpandMI(MachineBasicBlock &MBB,
                                 MVT::i16);
 
   case M68k::MOV8cd:
+  case M68k::MOV32cd:
     return TII->ExpandCCR(MIB, /*IsToCCR=*/true);
+
   case M68k::MOV8dc:
+  case M68k::MOV32dc:
     return TII->ExpandCCR(MIB, /*IsToCCR=*/false);
 
   case M68k::MOVM8jm_P:
diff --git a/llvm/lib/Target/M68k/M68kInstrData.td b/llvm/lib/Target/M68k/M68kInstrData.td
index dc777a933e2786..be2d43ce1de3ae 100644
--- a/llvm/lib/Target/M68k/M68kInstrData.td
+++ b/llvm/lib/Target/M68k/M68kInstrData.td
@@ -385,12 +385,14 @@ class MxMoveToCCRPseudo<MxOperand MEMOp>
 
 let mayLoad = 1 in
 foreach AM = MxMoveSupportedAMs in {
+  def MOV32c # AM : MxMoveToCCRPseudo<!cast<MxOpBundle>("MxOp32AddrMode_"#AM).Op>;
   def MOV16c # AM : MxMoveToCCR<!cast<MxOpBundle>("MxOp16AddrMode_"#AM).Op,
                                 !cast<MxEncMemOp>("MxMoveSrcOpEnc_"#AM)>;
   def MOV8c # AM  : MxMoveToCCRPseudo<!cast<MxOpBundle>("MxOp8AddrMode_"#AM).Op>;
 } // foreach AM
 
 // Only data register is allowed.
+def MOV32cd : MxMoveToCCRPseudo<MxOp32AddrMode_d.Op>;
 def MOV16cd : MxMoveToCCR<MxOp16AddrMode_d.Op, MxMoveSrcOpEnc_d>;
 def MOV8cd  : MxMoveToCCRPseudo<MxOp8AddrMode_d.Op>;
 
@@ -423,6 +425,9 @@ class MxMoveFromCCRPseudo<MxOperand MEMOp>
 
 let mayStore = 1 in
 foreach AM = MxMoveSupportedAMs in {
+  def MOV32 # AM # c
+    : MxMoveFromCCR_M<!cast<MxOpBundle>("MxOp32AddrMode_"#AM).Op,
+                      !cast<MxEncMemOp>("MxMoveDstOpEnc_"#AM)>;
   def MOV16 # AM # c
     : MxMoveFromCCR_M<!cast<MxOpBundle>("MxOp16AddrMode_"#AM).Op,
                       !cast<MxEncMemOp>("MxMoveDstOpEnc_"#AM)>;
@@ -431,6 +436,7 @@ foreach AM = MxMoveSupportedAMs in {
 } // foreach AM
 
 // Only data register is allowed.
+def MOV32dc : MxMoveFromCCRPseudo<MxOp32AddrMode_d.Op>;
 def MOV16dc : MxMoveFromCCR_R;
 def MOV8dc  : MxMoveFromCCRPseudo<MxOp8AddrMode_d.Op>;
 
diff --git a/llvm/lib/Target/M68k/M68kInstrInfo.cpp b/llvm/lib/Target/M68k/M68kInstrInfo.cpp
index 2d9285f89b74ae..53bc981fb4a322 100644
--- a/llvm/lib/Target/M68k/M68kInstrInfo.cpp
+++ b/llvm/lib/Target/M68k/M68kInstrInfo.cpp
@@ -757,13 +757,28 @@ void M68kInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
   bool ToSR = DstReg == M68k::SR;
 
   if (FromCCR) {
-    assert(M68k::DR8RegClass.contains(DstReg) &&
-           "Need DR8 register to copy CCR");
-    Opc = M68k::MOV8dc;
+    if (M68k::DR8RegClass.contains(DstReg))
+      Opc = M68k::MOV8dc;
+    else if (M68k::DR16RegClass.contains(DstReg))
+      Opc = M68k::MOV16dc;
+    else if (M68k::DR32RegClass.contains(DstReg))
+      Opc = M68k::MOV32dc;
+    else {
+    LLVM_DEBUG(dbgs() << "Cannot copy CCR to " << RI.getName(DstReg) 
+                << "(" << RI.getRegClass(DstReg) << ")\n");
+    llvm_unreachable("Invalid register for MOVE from CCR");
+    }
   } else if (ToCCR) {
-    assert(M68k::DR8RegClass.contains(SrcReg) &&
-           "Need DR8 register to copy CCR");
-    Opc = M68k::MOV8cd;
+    if (M68k::DR8RegClass.contains(SrcReg))
+      Opc = M68k::MOV8cd;
+    else if (M68k::DR16RegClass.contains(SrcReg))
+      Opc = M68k::MOV16cd;
+    else if (M68k::DR32RegClass.contains(SrcReg))
+      Opc = M68k::MOV32cd;
+    else {
+      LLVM_DEBUG(dbgs() << "Cannot copy " << RI.getName(SrcReg) << " to CCR" << '\n');
+      llvm_unreachable("Invalid register for MOVE to CCR");
+    }
   } else if (FromSR || ToSR)
     llvm_unreachable("Cannot emit SR copy instruction");
 

>From 72871273886173ce756c583a4f598c95edcc88f3 Mon Sep 17 00:00:00 2001
From: kirk <knickish at gmail.com>
Date: Tue, 29 Oct 2024 21:56:31 +0000
Subject: [PATCH 2/2] working CCR->DR32 copy

---
 llvm/lib/Target/M68k/M68kInstrData.td        |  6 +-
 llvm/lib/Target/M68k/M68kInstrInfo.cpp       | 65 ++++++++++++++++----
 llvm/test/CodeGen/M68k/null-regsel-switch.ll | 23 +++++++
 3 files changed, 81 insertions(+), 13 deletions(-)
 create mode 100644 llvm/test/CodeGen/M68k/null-regsel-switch.ll

diff --git a/llvm/lib/Target/M68k/M68kInstrData.td b/llvm/lib/Target/M68k/M68kInstrData.td
index be2d43ce1de3ae..2f32502cd001f3 100644
--- a/llvm/lib/Target/M68k/M68kInstrData.td
+++ b/llvm/lib/Target/M68k/M68kInstrData.td
@@ -421,6 +421,8 @@ class MxMoveFromCCR_M<MxOperand MEMOp, MxEncMemOp DST_ENC>
 
 class MxMoveFromCCRPseudo<MxOperand MEMOp>
     : MxPseudo<(outs), (ins MEMOp:$dst, CCRC:$src)>;
+class MxMoveFromCCR_RPseudo<MxOperand MEMOp>
+    : MxPseudo<(outs MEMOp:$dst), (ins CCRC:$src)>;
 } // let Uses = [CCR]
 
 let mayStore = 1 in
@@ -436,9 +438,9 @@ foreach AM = MxMoveSupportedAMs in {
 } // foreach AM
 
 // Only data register is allowed.
-def MOV32dc : MxMoveFromCCRPseudo<MxOp32AddrMode_d.Op>;
+def MOV32dc : MxMoveFromCCR_RPseudo<MxOp32AddrMode_d.Op>;
 def MOV16dc : MxMoveFromCCR_R;
-def MOV8dc  : MxMoveFromCCRPseudo<MxOp8AddrMode_d.Op>;
+def MOV8dc  : MxMoveFromCCR_RPseudo<MxOp8AddrMode_d.Op>;
 
 //===----------------------------------------------------------------------===//
 // LEA
diff --git a/llvm/lib/Target/M68k/M68kInstrInfo.cpp b/llvm/lib/Target/M68k/M68kInstrInfo.cpp
index 53bc981fb4a322..3aeac30e5cebb8 100644
--- a/llvm/lib/Target/M68k/M68kInstrInfo.cpp
+++ b/llvm/lib/Target/M68k/M68kInstrInfo.cpp
@@ -23,12 +23,16 @@
 #include "llvm/CodeGen/LivePhysRegs.h"
 #include "llvm/CodeGen/LiveVariables.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGenTypes/MachineValueType.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Regex.h"
 
+#include <cassert>
 #include <functional>
+#include <iterator>
 
 using namespace llvm;
 
@@ -571,6 +575,49 @@ bool M68kInstrInfo::ExpandPUSH_POP(MachineInstrBuilder &MIB,
 }
 
 bool M68kInstrInfo::ExpandCCR(MachineInstrBuilder &MIB, bool IsToCCR) const {
+  switch (MIB->getOpcode()) {
+  case M68k::MOV32dc: {
+    // We're trying to get an i32 value out of an i16 op
+    // Copy the value to the 16Lo subreg, then zext it
+    auto &Opd = MIB->getOperand(0);
+    auto OriginalReg = Opd.getReg();
+    auto SubReg =
+        getRegisterInfo().getSubReg(Opd.getReg(), M68k::MxSubRegIndex16Lo);
+    Opd.setReg(SubReg);
+    assert(SubReg.id() && "No viable SUB register available");
+
+    MachineBasicBlock::iterator I = MIB.getInstr();
+    { // debugging
+      auto Defs = I->all_defs();
+      for (auto Def : I->all_defs()) {
+        LLVM_DEBUG(dbgs() << "Defining:" << RI.getName(Def.getReg()) << '\n');
+      }
+      int DefsCount = std::distance(Defs.begin(), Defs.end());
+      LLVM_DEBUG(dbgs() << DefsCount << "registers defined" << '\n');
+      assert(DefsCount == 1 && "Unexpected number of defs");
+    }
+    I++;
+    MachineBasicBlock &MBB = *MIB->getParent();
+    DebugLoc DL = MIB->getDebugLoc();
+
+    // Expand the value
+    copyPhysReg(MBB, I, DL, OriginalReg, SubReg, false);
+    // ANDI the expanded value to clear garbage
+    BuildMI(MBB, I, DL, get(M68k::AND32di), OriginalReg)
+        .addReg(OriginalReg)
+        .addImm(0xFFFF);
+    break;
+  }
+  case M68k::MOV8cd: {
+    // Promote used register to the next class
+    auto &Opd = MIB->getOperand(1);
+    Opd.setReg(getRegisterInfo().getMatchingSuperReg(
+        Opd.getReg(), M68k::MxSubRegIndex8Lo, &M68k::DR16RegClass));
+    break;
+  }
+  default:
+    break;
+  }
 
   // Replace the pseudo instruction with the real one
   if (IsToCCR)
@@ -579,11 +626,6 @@ bool M68kInstrInfo::ExpandCCR(MachineInstrBuilder &MIB, bool IsToCCR) const {
     // FIXME M68010 or later is required
     MIB->setDesc(get(M68k::MOV16dc));
 
-  // Promote used register to the next class
-  auto &Opd = MIB->getOperand(1);
-  Opd.setReg(getRegisterInfo().getMatchingSuperReg(
-      Opd.getReg(), M68k::MxSubRegIndex8Lo, &M68k::DR16RegClass));
-
   return true;
 }
 
@@ -761,12 +803,12 @@ void M68kInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
       Opc = M68k::MOV8dc;
     else if (M68k::DR16RegClass.contains(DstReg))
       Opc = M68k::MOV16dc;
-    else if (M68k::DR32RegClass.contains(DstReg))
+    else if (M68k::DR32RegClass.contains(DstReg)) {
       Opc = M68k::MOV32dc;
-    else {
-    LLVM_DEBUG(dbgs() << "Cannot copy CCR to " << RI.getName(DstReg) 
-                << "(" << RI.getRegClass(DstReg) << ")\n");
-    llvm_unreachable("Invalid register for MOVE from CCR");
+    } else {
+      LLVM_DEBUG(dbgs() << "Cannot copy CCR to " << RI.getName(DstReg) << "("
+                        << RI.getRegClass(DstReg) << ")\n");
+      llvm_unreachable("Invalid register for MOVE from CCR");
     }
   } else if (ToCCR) {
     if (M68k::DR8RegClass.contains(SrcReg))
@@ -776,7 +818,8 @@ void M68kInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
     else if (M68k::DR32RegClass.contains(SrcReg))
       Opc = M68k::MOV32cd;
     else {
-      LLVM_DEBUG(dbgs() << "Cannot copy " << RI.getName(SrcReg) << " to CCR" << '\n');
+      LLVM_DEBUG(dbgs() << "Cannot copy " << RI.getName(SrcReg) << " to CCR"
+                        << '\n');
       llvm_unreachable("Invalid register for MOVE to CCR");
     }
   } else if (FromSR || ToSR)
diff --git a/llvm/test/CodeGen/M68k/null-regsel-switch.ll b/llvm/test/CodeGen/M68k/null-regsel-switch.ll
new file mode 100644
index 00000000000000..16655720f0a5d2
--- /dev/null
+++ b/llvm/test/CodeGen/M68k/null-regsel-switch.ll
@@ -0,0 +1,23 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -mtriple=m68k-linux  -mcpu=M68020 --verify-machineinstrs | FileCheck %s
+
+define internal void @test_func(i32 %self, ptr nonnull %value) {
+start:
+  %2 = icmp eq i32 %self, 0
+  %3 = select i1 %2, i32 0, i32 1
+  switch i32 %3, label %exit [
+    i32 0, label %nonnull
+    i32 1, label %null
+  ]
+
+nonnull:                                              ; preds = %start
+  store ptr %value, ptr null, align 2
+  br label %exit
+
+null:                                              ; preds = %start
+  store ptr %value, ptr null, align 2
+  br label %exit
+
+exit:                                              ; preds = %nonnull, %null
+  ret void
+}
\ No newline at end of file



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