[mips][msa] MSA loads and stores have a 10-bit offset. Account for this when lowering FrameIndex.

This prevents the compiler from emitting invalid ld.[bhwd]'s and st.[bhwd]'s
when the stack frame is between 512 and 32,768 bytes in size.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195973 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 132 insertions, 5 deletions

diff --git a/lib/Target/Mips/MipsSERegisterInfo.cpp b/lib/Target/Mips/MipsSERegisterInfo.cpp
index 2be054eef5..2d440840aa 100644
--- a/lib/Target/Mips/MipsSERegisterInfo.cpp
+++ b/lib/Target/Mips/MipsSERegisterInfo.cpp
@@ -62,6 +62,24 @@ MipsSERegisterInfo::intRegClass(unsigned Size) const {
   return &Mips::GPR64RegClass;
 }
 
+/// Determine whether a given opcode is an MSA load/store (supporting 10-bit
+/// offsets) or a non-MSA load/store (supporting 16-bit offsets).
+static inline bool isMSALoadOrStore(const unsigned Opcode) {
+  switch (Opcode) {
+  case Mips::LD_B:
+  case Mips::LD_H:
+  case Mips::LD_W:
+  case Mips::LD_D:
+  case Mips::ST_B:
+  case Mips::ST_H:
+  case Mips::ST_W:
+  case Mips::ST_D:
+    return true;
+  default:
+    return false;
+  }
+}
+
 void MipsSERegisterInfo::eliminateFI(MachineBasicBlock::iterator II,
                                      unsigned OpNo, int FrameIndex,
                                      uint64_t StackSize,
@@ -111,18 +129,42 @@ void MipsSERegisterInfo::eliminateFI(MachineBasicBlock::iterator II,
 
   DEBUG(errs() << "Offset     : " << Offset << "\n" << "<--------->\n");
 
-  // If MI is not a debug value, make sure Offset fits in the 16-bit immediate
-  // field.
   if (!MI.isDebugValue()) {
-    if (!isInt<16>(Offset)) {
+    // Make sure Offset fits within the field available.
+    // For MSA instructions, this is a 10-bit signed immediate, otherwise it is
+    // a 16-bit signed immediate.
+    unsigned OffsetBitSize = isMSALoadOrStore(MI.getOpcode()) ? 10 : 16;
+
+    if (OffsetBitSize == 10 && !isInt<10>(Offset) && isInt<16>(Offset)) {
+      // If we have an offset that needs to fit into a signed 10-bit immediate
+      // and doesn't, but does fit into 16-bits then use an ADDiu
+      MachineBasicBlock &MBB = *MI.getParent();
+      DebugLoc DL = II->getDebugLoc();
+      unsigned ADDiu = Subtarget.isABI_N64() ? Mips::DADDiu : Mips::ADDiu;
+      const TargetRegisterClass *RC =
+          Subtarget.isABI_N64() ? &Mips::GPR64RegClass : &Mips::GPR32RegClass;
+      MachineRegisterInfo &RegInfo = MBB.getParent()->getRegInfo();
+      unsigned Reg = RegInfo.createVirtualRegister(RC);
+      const MipsSEInstrInfo &TII =
+          *static_cast<const MipsSEInstrInfo *>(
+               MBB.getParent()->getTarget().getInstrInfo());
+      BuildMI(MBB, II, DL, TII.get(ADDiu), Reg).addReg(FrameReg).addImm(Offset);
+
+      FrameReg = Reg;
+      Offset = 0;
+      IsKill = true;
+    } else if (!isInt<16>(Offset)) {
+      // Otherwise split the offset into 16-bit pieces and add it in multiple
+      // instructions.
       MachineBasicBlock &MBB = *MI.getParent();
       DebugLoc DL = II->getDebugLoc();
       unsigned ADDu = Subtarget.isABI_N64() ? Mips::DADDu : Mips::ADDu;
-      unsigned NewImm;
+      unsigned NewImm = 0;
       const MipsSEInstrInfo &TII =
           *static_cast<const MipsSEInstrInfo *>(
                MBB.getParent()->getTarget().getInstrInfo());
-      unsigned Reg = TII.loadImmediate(Offset, MBB, II, DL, &NewImm);
+      unsigned Reg = TII.loadImmediate(Offset, MBB, II, DL,
+                                       OffsetBitSize == 16 ? &NewImm : NULL);
       BuildMI(MBB, II, DL, TII.get(ADDu), Reg).addReg(FrameReg)
         .addReg(Reg, RegState::Kill);
 
diff --git a/test/CodeGen/Mips/msa/frameindex.ll b/test/CodeGen/Mips/msa/frameindex.ll
new file mode 100644
index 0000000000..3088e1ba98
--- /dev/null
+++ b/test/CodeGen/Mips/msa/frameindex.ll
@@ -0,0 +1,85 @@
+; RUN: llc -march=mips -mattr=+msa,+fp64 < %s | FileCheck -check-prefix=MIPS32-AE -check-prefix=MIPS32-BE %s
+; RUN: llc -march=mipsel -mattr=+msa,+fp64 < %s | FileCheck -check-prefix=MIPS32-AE -check-prefix=MIPS32-LE %s
+
+define void @loadstore_v16i8_near() nounwind {
+  ; MIPS32-AE: loadstore_v16i8_near:
+
+  %1 = alloca <16 x i8>
+  %2 = load volatile <16 x i8>* %1
+  ; MIPS32-AE: ld.b [[R1:\$w[0-9]+]], 0($sp)
+  store volatile <16 x i8> %2, <16 x i8>* %1
+  ; MIPS32-AE: st.b [[R1]], 0($sp)
+
+  ret void
+  ; MIPS32-AE: .size loadstore_v16i8_near
+}
+
+define void @loadstore_v16i8_just_under_simm10() nounwind {
+  ; MIPS32-AE: loadstore_v16i8_just_under_simm10:
+
+  %1 = alloca <16 x i8>
+  %2 = alloca [496 x i8] ; Push the frame right up to 512 bytes
+
+  %3 = load volatile <16 x i8>* %1
+  ; MIPS32-AE: ld.b [[R1:\$w[0-9]+]], 496($sp)
+  store volatile <16 x i8> %3, <16 x i8>* %1
+  ; MIPS32-AE: st.b [[R1]], 496($sp)
+
+  ret void
+  ; MIPS32-AE: .size loadstore_v16i8_just_under_simm10
+}
+
+define void @loadstore_v16i8_just_over_simm10() nounwind {
+  ; MIPS32-AE: loadstore_v16i8_just_over_simm10:
+
+  %1 = alloca <16 x i8>
+  %2 = alloca [497 x i8] ; Push the frame just over 512 bytes
+
+  %3 = load volatile <16 x i8>* %1
+  ; MIPS32-AE: addiu [[BASE:\$[0-9]+]], $sp, 512
+  ; MIPS32-AE: ld.b [[R1:\$w[0-9]+]], 0([[BASE]])
+  store volatile <16 x i8> %3, <16 x i8>* %1
+  ; MIPS32-AE: addiu [[BASE:\$[0-9]+]], $sp, 512
+  ; MIPS32-AE: st.b [[R1]], 0([[BASE]])
+
+  ret void
+  ; MIPS32-AE: .size loadstore_v16i8_just_over_simm10
+}
+
+define void @loadstore_v16i8_just_under_simm16() nounwind {
+  ; MIPS32-AE: loadstore_v16i8_just_under_simm16:
+
+  %1 = alloca <16 x i8>
+  %2 = alloca [32752 x i8] ; Push the frame right up to 32768 bytes
+
+  %3 = load volatile <16 x i8>* %1
+  ; MIPS32-AE: ori [[R2:\$[0-9]+]], $zero, 32768
+  ; MIPS32-AE: addu [[BASE:\$[0-9]+]], $sp, [[R2]]
+  ; MIPS32-AE: ld.b [[R1:\$w[0-9]+]], 0([[BASE]])
+  store volatile <16 x i8> %3, <16 x i8>* %1
+  ; MIPS32-AE: ori [[R2:\$[0-9]+]], $zero, 32768
+  ; MIPS32-AE: addu [[BASE:\$[0-9]+]], $sp, [[R2]]
+  ; MIPS32-AE: st.b [[R1]], 0([[BASE]])
+
+  ret void
+  ; MIPS32-AE: .size loadstore_v16i8_just_under_simm16
+}
+
+define void @loadstore_v16i8_just_over_simm16() nounwind {
+  ; MIPS32-AE: loadstore_v16i8_just_over_simm16:
+
+  %1 = alloca <16 x i8>
+  %2 = alloca [32753 x i8] ; Push the frame just over 32768 bytes
+
+  %3 = load volatile <16 x i8>* %1
+  ; MIPS32-AE: ori [[R2:\$[0-9]+]], $zero, 32768
+  ; MIPS32-AE: addu [[BASE:\$[0-9]+]], $sp, [[R2]]
+  ; MIPS32-AE: ld.b [[R1:\$w[0-9]+]], 0([[BASE]])
+  store volatile <16 x i8> %3, <16 x i8>* %1
+  ; MIPS32-AE: ori [[R2:\$[0-9]+]], $zero, 32768
+  ; MIPS32-AE: addu [[BASE:\$[0-9]+]], $sp, [[R2]]
+  ; MIPS32-AE: st.b [[R1]], 0([[BASE]])
+
+  ret void
+  ; MIPS32-AE: .size loadstore_v16i8_just_over_simm16
+}