GlobalISel: Add helper to LLT to get a scalar or vector

[arsenm]

Add a second version

[volkan]

Could you add a test to unittests/CodeGen/LowLevelTypeTest.cpp?

include/llvm/Support/LowLevelTypeImpl.h

79

This can be replaced with:

return scalarOrVector(NumElements, LLT::scalar(ScalarSize));

[paquette]

include/llvm/Support/LowLevelTypeImpl.h

73

What happens if NumElements == 0? Seems good to assert that it's greater than 0 in both functions, unless a vector of 0 elements is the desired behaviour.

[arsenm]

include/llvm/Support/LowLevelTypeImpl.h

73

I think that would be redundant with the assert in vector()

[arsenm]

Simplify, add test

[paquette]

LGTM

[arsenm]

r352136

include/llvm/Support/LowLevelTypeImpl.h

public:
   static LLT vector(uint16_t NumElements, LLT ScalarTy) {
     assert(NumElements > 1 && "invalid number of vector elements");
     assert(!ScalarTy.isVector() && "invalid vector element type");
     return LLT{ScalarTy.isPointer(), /*isVector=*/true, NumElements,
                ScalarTy.getSizeInBits(),
                ScalarTy.isPointer() ? ScalarTy.getAddressSpace() : 0};
   }
 
+  static LLT scalarOrVector(uint16_t NumElements, LLT ScalarTy) {
+    return NumElements == 1 ? ScalarTy : LLT::vector(NumElements, ScalarTy);
+  }
+
+  static LLT scalarOrVector(uint16_t NumElements, unsigned ScalarSize) {
+    return scalarOrVector(NumElements, LLT::scalar(ScalarSize));
+  }
+
   explicit LLT(bool isPointer, bool isVector, uint16_t NumElements,
                unsigned SizeInBits, unsigned AddressSpace) {
     init(isPointer, isVector, NumElements, SizeInBits, AddressSpace);
   }
   explicit LLT() : IsPointer(false), IsVector(false), RawData(0) {}
 
   explicit LLT(MVT VT);
 

unittests/CodeGen/LowLevelTypeTest.cpp

for (uint16_t Elts : {2U, 3U, 4U, 32U, 0xffU}) {
       // Test Type->LLT conversion.
       Type *IRSTy = IntegerType::get(C, S);
       Type *IRTy = VectorType::get(IRSTy, Elts);
       EXPECT_EQ(VTy, getLLTForType(*IRTy, DL));
     }
   }
 }
 
+TEST(LowLevelTypeTest, ScalarOrVector) {
+  // Test version with number of bits for scalar type.
+  EXPECT_EQ(LLT::scalar(32), LLT::scalarOrVector(1, 32));
+  EXPECT_EQ(LLT::vector(2, 32), LLT::scalarOrVector(2, 32));
+
+  // Test version with LLT for scalar type.
+  EXPECT_EQ(LLT::scalar(32), LLT::scalarOrVector(1, LLT::scalar(32)));
+  EXPECT_EQ(LLT::vector(2, 32), LLT::scalarOrVector(2, LLT::scalar(32)));
+
+  // Test with pointer elements.
+  EXPECT_EQ(LLT::pointer(1, 32), LLT::scalarOrVector(1, LLT::pointer(1, 32)));
+  EXPECT_EQ(LLT::vector(2, LLT::pointer(1, 32)),
+            LLT::scalarOrVector(2, LLT::pointer(1, 32)));
+}
+
 TEST(LowLevelTypeTest, Pointer) {
   LLVMContext C;
   DataLayout DL("");
 
   for (unsigned AS : {0U, 1U, 127U, 0xffffU}) {
     const LLT Ty = LLT::pointer(AS, DL.getPointerSizeInBits(AS));
     const LLT VTy = LLT::vector(4, Ty);