commit fde01046498b67510357bd9897dd68bfb3e8b110
author Justin Bogner <mail@justinbogner.com> Wed Jan 18 17:29:54 2017 +0000
committer Justin Bogner <mail@justinbogner.com> Wed Jan 18 17:29:54 2017 +0000
tree b91db2557338a9e040ccd5770b48641037be5d51
parent cb60161a25ef63d612e5dc614ceb97f68672cc3c

GlobalISel: Implement narrowing for G_STORE

Legalize stores of types that are too wide by breaking them up into
sequences of smaller stores.

llvm-svn: 292412

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index eb25b6c..bb4f2cf 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -125,6 +125,9 @@
   // FIXME: Don't know how to handle secondary types yet.
   if (TypeIdx != 0)
     return UnableToLegalize;
+
+  MIRBuilder.setInstr(MI);
+
   switch (MI.getOpcode()) {
   default:
     return UnableToLegalize;
@@ -134,8 +137,6 @@
     int NumParts = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits() /
                    NarrowTy.getSizeInBits();
 
-    MIRBuilder.setInstr(MI);
-
     SmallVector<unsigned, 2> Src1Regs, Src2Regs, DstRegs;
     SmallVector<uint64_t, 2> Indexes;
     extractParts(MI.getOperand(1).getReg(), NarrowTy, NumParts, Src1Regs);
@@ -160,6 +161,26 @@
     MI.eraseFromParent();
     return Legalized;
   }
+  case TargetOpcode::G_STORE: {
+    unsigned NarrowSize = NarrowTy.getSizeInBits();
+    int NumParts =
+        MRI.getType(MI.getOperand(0).getReg()).getSizeInBits() / NarrowSize;
+    LLT NarrowPtrTy = LLT::pointer(
+        MRI.getType(MI.getOperand(1).getReg()).getAddressSpace(), NarrowSize);
+
+    SmallVector<unsigned, 2> SrcRegs;
+    extractParts(MI.getOperand(0).getReg(), NarrowTy, NumParts, SrcRegs);
+
+    for (int i = 0; i < NumParts; ++i) {
+      unsigned DstReg = MRI.createGenericVirtualRegister(NarrowPtrTy);
+      unsigned Offset = MRI.createGenericVirtualRegister(LLT::scalar(64));
+      MIRBuilder.buildConstant(Offset, i * NarrowSize / 8);
+      MIRBuilder.buildGEP(DstReg, MI.getOperand(1).getReg(), Offset);
+      MIRBuilder.buildStore(SrcRegs[i], DstReg, **MI.memoperands_begin());
+    }
+    MI.eraseFromParent();
+    return Legalized;
+  }
   }
 }