GlobalISel: legalize GEP instructions with small offsets.

llvm-svn: 281602

2 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp b/llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp
index 7c32cd5314b..6d181396079 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp
@@ -281,6 +281,13 @@ MachineLegalizeHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx,
     MI.eraseFromParent();
     return Legalized;
   }
+  case TargetOpcode::G_GEP: {
+    assert(TypeIdx == 1 && "unable to legalize pointer of GEP");
+    unsigned OffsetExt = MRI.createGenericVirtualRegister(WideTy);
+    MIRBuilder.buildSExt(OffsetExt, MI.getOperand(2).getReg());
+    MI.getOperand(2).setReg(OffsetExt);
+    return Legalized;
+  }
   }
 }
 
diff --git a/llvm/lib/Target/AArch64/AArch64MachineLegalizer.cpp b/llvm/lib/Target/AArch64/AArch64MachineLegalizer.cpp
index a5a7ed60ba1..653c7d53e69 100644
--- a/llvm/lib/Target/AArch64/AArch64MachineLegalizer.cpp
+++ b/llvm/lib/Target/AArch64/AArch64MachineLegalizer.cpp
@@ -43,6 +43,12 @@ AArch64MachineLegalizer::AArch64MachineLegalizer() {
       setAction({BinOp, Ty}, Legal);
   }
 
+  setAction({G_GEP, p0}, Legal);
+  setAction({G_GEP, 1, s64}, Legal);
+
+  for (auto Ty : {s1, s8, s16, s32})
+    setAction({G_GEP, 1, Ty}, WidenScalar);
+
   for (auto BinOp : {G_LSHR, G_ASHR, G_SDIV, G_UDIV}) {
     for (auto Ty : {s32, s64})
       setAction({BinOp, Ty}, Legal);