commit ea904f9424cc37c5ff7ac595e465ede2a10fdf0d
author Tim Northover <tnorthover@apple.com> Fri Aug 19 22:40:00 2016 +0000
committer Tim Northover <tnorthover@apple.com> Fri Aug 19 22:40:00 2016 +0000
tree a6f53aec83820790c56ad70b565f333f940ad292
parent fa7de606c439d90665ef25f0c6d447a9476c2fc6

GlobalISel: teach legalizer how to handle integer constants.

llvm-svn: 279340

llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp b/llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp
index 29fdee8..632d629 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineLegalizeHelper.cpp
@@ -104,6 +104,7 @@
 
 MachineLegalizeHelper::LegalizeResult
 MachineLegalizeHelper::widenScalar(MachineInstr &MI, LLT WideTy) {
+  unsigned WideSize = WideTy.getSizeInBits();
   switch (MI.getOpcode()) {
   default:
     return UnableToLegalize;
@@ -116,7 +117,6 @@
     // Perform operation at larger width (any extension is fine here, high bits
     // don't affect the result) and then truncate the result back to the
     // original type.
-    unsigned WideSize = WideTy.getSizeInBits();
 
     MIRBuilder.setInstr(MI);
 
@@ -133,6 +133,14 @@
     MI.eraseFromParent();
     return Legalized;
   }
+  case TargetOpcode::G_CONSTANT: {
+    MIRBuilder.setInstr(MI);
+    unsigned DstExt = MRI.createGenericVirtualRegister(WideSize);
+    MIRBuilder.buildConstant(WideTy, DstExt, MI.getOperand(1).getImm());
+    MIRBuilder.buildTrunc(MI.getType(), MI.getOperand(0).getReg(), DstExt);
+    MI.eraseFromParent();
+    return Legalized;
+  }
   }
 }
 

llvm/lib/CodeGen/GlobalISel/MachineLegalizer.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/MachineLegalizer.cpp b/llvm/lib/CodeGen/GlobalISel/MachineLegalizer.cpp
index 881b502..fa23627 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineLegalizer.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineLegalizer.cpp
@@ -119,8 +119,9 @@
                          [&](LLT Ty) -> LLT { return Ty.halfScalarSize(); });
   }
   case WidenScalar: {
-    return findLegalType(Opcode, Ty,
-                         [&](LLT Ty) -> LLT { return Ty.doubleScalarSize(); });
+    return findLegalType(Opcode, Ty, [&](LLT Ty) -> LLT {
+      return Ty.getSizeInBits() < 8 ? LLT::scalar(8) : Ty.doubleScalarSize();
+    });
   }
   case FewerElements: {
     return findLegalType(Opcode, Ty,