AArch64: Fix XSeqPairs/WSeqPairs problems

- Fix spill/reloads of XSeqPairs failing with vregs (only physregs
  worked correctly)
- Add missing spill/reload code for WSeqPairs class

Differential Revision: https://reviews.llvm.org/D52761

2 files changed, 110 insertions, 18 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index da555665a75..3bc3a3abe35 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -2744,6 +2744,29 @@ void AArch64InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
   llvm_unreachable("unimplemented reg-to-reg copy");
 }
 
+static void storeRegPairToStackSlot(const TargetRegisterInfo &TRI,
+                                    MachineBasicBlock &MBB,
+                                    MachineBasicBlock::iterator InsertBefore,
+                                    const MCInstrDesc &MCID,
+                                    unsigned SrcReg, bool IsKill,
+                                    unsigned SubIdx0, unsigned SubIdx1, int FI,
+                                    MachineMemOperand *MMO) {
+  unsigned SrcReg0 = SrcReg;
+  unsigned SrcReg1 = SrcReg;
+  if (TargetRegisterInfo::isPhysicalRegister(SrcReg)) {
+    SrcReg0 = TRI.getSubReg(SrcReg, SubIdx0);
+    SubIdx0 = 0;
+    SrcReg1 = TRI.getSubReg(SrcReg, SubIdx1);
+    SubIdx1 = 0;
+  }
+  BuildMI(MBB, InsertBefore, DebugLoc(), MCID)
+      .addReg(SrcReg0, getKillRegState(IsKill), SubIdx0)
+      .addReg(SrcReg1, getKillRegState(IsKill), SubIdx1)
+      .addFrameIndex(FI)
+      .addImm(0)
+      .addMemOperand(MMO);
+}
+
 void AArch64InstrInfo::storeRegToStackSlot(
     MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, unsigned SrcReg,
     bool isKill, int FI, const TargetRegisterClass *RC,
@@ -2786,8 +2809,14 @@ void AArch64InstrInfo::storeRegToStackSlot(
         MF.getRegInfo().constrainRegClass(SrcReg, &AArch64::GPR64RegClass);
       else
         assert(SrcReg != AArch64::SP);
-    } else if (AArch64::FPR64RegClass.hasSubClassEq(RC))
+    } else if (AArch64::FPR64RegClass.hasSubClassEq(RC)) {
       Opc = AArch64::STRDui;
+    } else if (AArch64::WSeqPairsClassRegClass.hasSubClassEq(RC)) {
+      storeRegPairToStackSlot(getRegisterInfo(), MBB, MBBI,
+                              get(AArch64::STPWi), SrcReg, isKill,
+                              AArch64::sube32, AArch64::subo32, FI, MMO);
+      return;
+    }
     break;
   case 16:
     if (AArch64::FPR128RegClass.hasSubClassEq(RC))
@@ -2797,14 +2826,9 @@ void AArch64InstrInfo::storeRegToStackSlot(
       Opc = AArch64::ST1Twov1d;
       Offset = false;
     } else if (AArch64::XSeqPairsClassRegClass.hasSubClassEq(RC)) {
-      BuildMI(MBB, MBBI, DL, get(AArch64::STPXi))
-          .addReg(TRI->getSubReg(SrcReg, AArch64::sube64),
-                  getKillRegState(isKill))
-          .addReg(TRI->getSubReg(SrcReg, AArch64::subo64),
-                  getKillRegState(isKill))
-          .addFrameIndex(FI)
-          .addImm(0)
-          .addMemOperand(MMO);
+      storeRegPairToStackSlot(getRegisterInfo(), MBB, MBBI,
+                              get(AArch64::STPXi), SrcReg, isKill,
+                              AArch64::sube64, AArch64::subo64, FI, MMO);
       return;
     }
     break;
@@ -2852,6 +2876,31 @@ void AArch64InstrInfo::storeRegToStackSlot(
   MI.addMemOperand(MMO);
 }
 
+static void loadRegPairFromStackSlot(const TargetRegisterInfo &TRI,
+                                     MachineBasicBlock &MBB,
+                                     MachineBasicBlock::iterator InsertBefore,
+                                     const MCInstrDesc &MCID,
+                                     unsigned DestReg, unsigned SubIdx0,
+                                     unsigned SubIdx1, int FI,
+                                     MachineMemOperand *MMO) {
+  unsigned DestReg0 = DestReg;
+  unsigned DestReg1 = DestReg;
+  bool IsUndef = true;
+  if (TargetRegisterInfo::isPhysicalRegister(DestReg)) {
+    DestReg0 = TRI.getSubReg(DestReg, SubIdx0);
+    SubIdx0 = 0;
+    DestReg1 = TRI.getSubReg(DestReg, SubIdx1);
+    SubIdx1 = 0;
+    IsUndef = false;
+  }
+  BuildMI(MBB, InsertBefore, DebugLoc(), MCID)
+      .addReg(DestReg0, RegState::Define | getUndefRegState(IsUndef), SubIdx0)
+      .addReg(DestReg1, RegState::Define | getUndefRegState(IsUndef), SubIdx1)
+      .addFrameIndex(FI)
+      .addImm(0)
+      .addMemOperand(MMO);
+}
+
 void AArch64InstrInfo::loadRegFromStackSlot(
     MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, unsigned DestReg,
     int FI, const TargetRegisterClass *RC,
@@ -2894,8 +2943,14 @@ void AArch64InstrInfo::loadRegFromStackSlot(
         MF.getRegInfo().constrainRegClass(DestReg, &AArch64::GPR64RegClass);
       else
         assert(DestReg != AArch64::SP);
-    } else if (AArch64::FPR64RegClass.hasSubClassEq(RC))
+    } else if (AArch64::FPR64RegClass.hasSubClassEq(RC)) {
       Opc = AArch64::LDRDui;
+    } else if (AArch64::WSeqPairsClassRegClass.hasSubClassEq(RC)) {
+      loadRegPairFromStackSlot(getRegisterInfo(), MBB, MBBI,
+                               get(AArch64::LDPWi), DestReg, AArch64::sube32,
+                               AArch64::subo32, FI, MMO);
+      return;
+    }
     break;
   case 16:
     if (AArch64::FPR128RegClass.hasSubClassEq(RC))
@@ -2905,14 +2960,9 @@ void AArch64InstrInfo::loadRegFromStackSlot(
       Opc = AArch64::LD1Twov1d;
       Offset = false;
     } else if (AArch64::XSeqPairsClassRegClass.hasSubClassEq(RC)) {
-      BuildMI(MBB, MBBI, DL, get(AArch64::LDPXi))
-          .addReg(TRI->getSubReg(DestReg, AArch64::sube64),
-                  getDefRegState(true))
-          .addReg(TRI->getSubReg(DestReg, AArch64::subo64),
-                  getDefRegState(true))
-          .addFrameIndex(FI)
-          .addImm(0)
-          .addMemOperand(MMO);
+      loadRegPairFromStackSlot(getRegisterInfo(), MBB, MBBI,
+                               get(AArch64::LDPXi), DestReg, AArch64::sube64,
+                               AArch64::subo64, FI, MMO);
       return;
     }
     break;
diff --git a/llvm/test/CodeGen/AArch64/seqpairspill.mir b/llvm/test/CodeGen/AArch64/seqpairspill.mir
new file mode 100644
index 00000000000..225e10ecfdb
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/seqpairspill.mir
@@ -0,0 +1,42 @@
+# RUN: llc -o - %s -mtriple=aarch64-- -mattr=+v8.1a -run-pass=greedy,virtregrewriter | FileCheck %s
+# Make sure spills/reloads from xseqpairs and wseqpairs work correctly.
+---
+# CHECK-LABEL: name: spill_reload_xseqpairs
+name: spill_reload_xseqpairs
+body: |
+  bb.0:
+    ; Check the spill/reload sequence for the %0 register
+    ; CHECK: renamable $[[REG0:[a-z0-9]+]]_[[REG1:[a-z0-9]+]] = CASPALX
+    ; CHECK-NEXT: STPXi renamable $[[REG0]], renamable $[[REG1]], %stack.0, 0, implicit killed $[[REG0]]_[[REG1]] :: (store 16 into %stack.0, align 8)
+    ; CHECK: INLINEASM
+    ; CHECK: renamable $[[REG2:[a-z0-9]+]], renamable $[[REG3:[a-z0-9]+]] = LDPXi %stack.0, 0, implicit-def $[[REG2]]_[[REG3]] :: (load 16 from %stack.0, align 8)
+    ; CHECK-NEXT: $xzr = COPY renamable $[[REG2]]
+    ; CHECK-NEXT: $xzr = COPY renamable $[[REG3]]
+    %0 : xseqpairsclass = IMPLICIT_DEF
+    %1 : xseqpairsclass = IMPLICIT_DEF
+    %2 : gpr64common = IMPLICIT_DEF
+    %0 = CASPALX %0, %1, %2
+    INLINEASM &" ", 0, 0, implicit def dead $x0, implicit def dead $x1, implicit def dead $x2, implicit def dead $x3, implicit def dead $x4, implicit def dead $x5, implicit def dead $x6, implicit def dead $x7, implicit def dead $x8, implicit def dead $x9, implicit def dead $x10, implicit def dead $x11, implicit def dead $x12, implicit def dead $x13, implicit def dead $x14, implicit def dead $x15, implicit def dead $x16, implicit def dead $x17, implicit def dead $x18, implicit def dead $x19, implicit def dead $x20, implicit def dead $x21, implicit def dead $x22, implicit def dead $x23, implicit def dead $x24, implicit def dead $x25, implicit def dead $x26, implicit def dead $x27, implicit def dead $x28, implicit def dead $fp, implicit def dead $lr
+    $xzr = COPY %0.sube64
+    $xzr = COPY %0.subo64
+...
+---
+# CHECK-LABEL: name: spill_reload_wseqpairs
+name: spill_reload_wseqpairs
+body: |
+  bb.0:
+    ; Check the spill/reload sequence for the %0 register
+    ; CHECK: $[[REG0:[a-z0-9]+]]_[[REG1:[a-z0-9]+]] = CASPALW
+    ; CHECK-NEXT: STPWi renamable $[[REG0]], renamable $[[REG1]], %stack.0, 0, implicit killed $[[REG0]]_[[REG1]] :: (store 8 into %stack.0, align 4)
+    ; CHECK: INLINEASM
+    ; CHECK: renamable $[[REG2:[a-z0-9]+]], renamable $[[REG3:[a-z0-9]+]] = LDPWi %stack.0, 0, implicit-def $[[REG2]]_[[REG3]] :: (load 8 from %stack.0, align 4)
+    ; CHECK-NEXT: $xzr = COPY renamable $[[REG2]]
+    ; CHECK-NEXT: $xzr = COPY renamable $[[REG3]]
+    %0 : wseqpairsclass = IMPLICIT_DEF
+    %1 : wseqpairsclass = IMPLICIT_DEF
+    %2 : gpr64common = IMPLICIT_DEF
+    %0 = CASPALW %0, %1, %2
+    INLINEASM &" ", 0, 0, implicit def dead $x0, implicit def dead $x1, implicit def dead $x2, implicit def dead $x3, implicit def dead $x4, implicit def dead $x5, implicit def dead $x6, implicit def dead $x7, implicit def dead $x8, implicit def dead $x9, implicit def dead $x10, implicit def dead $x11, implicit def dead $x12, implicit def dead $x13, implicit def dead $x14, implicit def dead $x15, implicit def dead $x16, implicit def dead $x17, implicit def dead $x18, implicit def dead $x19, implicit def dead $x20, implicit def dead $x21, implicit def dead $x22, implicit def dead $x23, implicit def dead $x24, implicit def dead $x25, implicit def dead $x26, implicit def dead $x27, implicit def dead $x28, implicit def dead $fp, implicit def dead $lr
+    $xzr = COPY %0.sube32
+    $xzr = COPY %0.subo32
+...