Revert "[GlobalISel] Add legalization support for non-power-2 loads and stores"

This introduces some runtime failures which I'll need to investigate further.

llvm-svn: 358771

1 files changed, 4 insertions, 95 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index e5c73f632c2..9ab14d52158 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1482,57 +1482,11 @@ LegalizerHelper::lower(MachineInstr &MI, unsigned TypeIdx, LLT Ty) {
     LLT DstTy = MRI.getType(DstReg);
     auto &MMO = **MI.memoperands_begin();
 
-    if (DstTy.getSizeInBits() == MMO.getSizeInBits()) {
-      if (MI.getOpcode() == TargetOpcode::G_LOAD) {
-        // This load needs splitting into power of 2 sized loads.
-        if (DstTy.isVector())
+    if (DstTy.getSizeInBits() == MMO.getSize() /* in bytes */ * 8) {
+      // In the case of G_LOAD, this was a non-extending load already and we're
+      // about to lower to the same instruction.
+      if (MI.getOpcode() == TargetOpcode::G_LOAD)
           return UnableToLegalize;
-        if (isPowerOf2_32(DstTy.getSizeInBits()))
-          return UnableToLegalize; // Don't know what we're being asked to do.
-
-        // Our strategy here is to generate anyextending loads for the smaller
-        // types up to next power-2 result type, and then combine the two larger
-        // result values together, before truncating back down to the non-pow-2
-        // type.
-        // E.g. v1 = i24 load =>
-        // v2 = i32 load (2 byte)
-        // v3 = i32 load (1 byte)
-        // v4 = i32 shl v2, 16
-        // v5 = i32 or v4, v3
-        // v1 = i24 trunc v5
-        // By doing this we generate the correct truncate which should get
-        // combined away as an artifact with a matching extend.
-        uint64_t LargeSplitSize = PowerOf2Floor(DstTy.getSizeInBits());
-        uint64_t SmallSplitSize = DstTy.getSizeInBits() - LargeSplitSize;
-
-        MachineFunction &MF = MIRBuilder.getMF();
-        MachineMemOperand *LargeMMO =
-            MF.getMachineMemOperand(&MMO, 0, LargeSplitSize / 8);
-        MachineMemOperand *SmallMMO = MF.getMachineMemOperand(
-            &MMO, LargeSplitSize / 8, SmallSplitSize / 8);
-
-        LLT PtrTy = MRI.getType(PtrReg);
-        unsigned AnyExtSize = NextPowerOf2(DstTy.getSizeInBits());
-        LLT AnyExtTy = LLT::scalar(AnyExtSize);
-        unsigned LargeLdReg = MRI.createGenericVirtualRegister(AnyExtTy);
-        unsigned SmallLdReg = MRI.createGenericVirtualRegister(AnyExtTy);
-        auto LargeLoad =
-            MIRBuilder.buildLoad(LargeLdReg, PtrReg, *LargeMMO);
-
-        auto OffsetCst =
-            MIRBuilder.buildConstant(LLT::scalar(64), LargeSplitSize / 8);
-        unsigned GEPReg = MRI.createGenericVirtualRegister(PtrTy);
-        auto SmallPtr = MIRBuilder.buildGEP(GEPReg, PtrReg, OffsetCst.getReg(0));
-        auto SmallLoad = MIRBuilder.buildLoad(SmallLdReg, SmallPtr.getReg(0),
-                                              *SmallMMO);
-
-        auto ShiftAmt = MIRBuilder.buildConstant(AnyExtTy, LargeSplitSize);
-        auto Shift = MIRBuilder.buildShl(AnyExtTy, LargeLoad, ShiftAmt);
-        auto Or = MIRBuilder.buildOr(AnyExtTy, Shift, SmallLoad);
-        MIRBuilder.buildTrunc(DstReg, {Or.getReg(0)});
-        MI.eraseFromParent();
-        return Legalized;
-      }
       MIRBuilder.buildLoad(DstReg, PtrReg, MMO);
       MI.eraseFromParent();
       return Legalized;
@@ -1561,51 +1515,6 @@ LegalizerHelper::lower(MachineInstr &MI, unsigned TypeIdx, LLT Ty) {
 
     return UnableToLegalize;
   }
-  case TargetOpcode::G_STORE: {
-    // Lower a non-power of 2 store into multiple pow-2 stores.
-    // E.g. split an i24 store into an i16 store + i8 store.
-    // We do this by first extending the stored value to the next largest power
-    // of 2 type, and then using truncating stores to store the components.
-    // By doing this, likewise with G_LOAD, generate an extend that can be
-    // artifact-combined away instead of leaving behind extracts.
-    unsigned SrcReg = MI.getOperand(0).getReg();
-    unsigned PtrReg = MI.getOperand(1).getReg();
-    LLT SrcTy = MRI.getType(SrcReg);
-    MachineMemOperand &MMO = **MI.memoperands_begin();
-    if (SrcTy.getSizeInBits() != MMO.getSizeInBits())
-      return UnableToLegalize;
-    if (SrcTy.isVector())
-      return UnableToLegalize;
-    if (isPowerOf2_32(SrcTy.getSizeInBits()))
-      return UnableToLegalize; // Don't know what we're being asked to do.
-
-    // Extend to the next pow-2.
-    const LLT ExtendTy = LLT::scalar(NextPowerOf2(SrcTy.getSizeInBits()));
-    auto ExtVal = MIRBuilder.buildAnyExt(ExtendTy, SrcReg);
-
-    // Obtain the smaller value by shifting away the larger value.
-    uint64_t LargeSplitSize = PowerOf2Floor(SrcTy.getSizeInBits());
-    uint64_t SmallSplitSize = SrcTy.getSizeInBits() - LargeSplitSize;
-    auto ShiftAmt = MIRBuilder.buildConstant(ExtendTy, LargeSplitSize);
-    auto SmallVal = MIRBuilder.buildLShr(ExtendTy, ExtVal, ShiftAmt);
-
-    // Generate the GEP and truncating stores.
-    LLT PtrTy = MRI.getType(PtrReg);
-    auto OffsetCst =
-        MIRBuilder.buildConstant(LLT::scalar(64), LargeSplitSize / 8);
-    unsigned GEPReg = MRI.createGenericVirtualRegister(PtrTy);
-    auto SmallPtr = MIRBuilder.buildGEP(GEPReg, PtrReg, OffsetCst.getReg(0));
-
-    MachineFunction &MF = MIRBuilder.getMF();
-    MachineMemOperand *LargeMMO =
-        MF.getMachineMemOperand(&MMO, 0, LargeSplitSize / 8);
-    MachineMemOperand *SmallMMO =
-        MF.getMachineMemOperand(&MMO, LargeSplitSize / 8, SmallSplitSize / 8);
-    MIRBuilder.buildStore(ExtVal.getReg(0), PtrReg, *LargeMMO);
-    MIRBuilder.buildStore(SmallVal.getReg(0), SmallPtr.getReg(0), *SmallMMO);
-    MI.eraseFromParent();
-    return Legalized;
-  }
   case TargetOpcode::G_CTLZ_ZERO_UNDEF:
   case TargetOpcode::G_CTTZ_ZERO_UNDEF:
   case TargetOpcode::G_CTLZ: