compiler: use GEP to index array

Author: dgryski

compiler/map.go

@@ -303,9 +303,8 @@ func (b *builder) zeroUndefBytes(typ types.Type, ptr llvm.Value) error {
 
 		for i := 0; i < llvmArrayType.ArrayLength(); i++ {
 			// for each element, first clear any undef bytes in the element itself
-			offset := b.targetData.ElementOffset(llvmArrayType, i)
-			llvmOffset := llvm.ConstInt(b.uintptrType, offset, false)
-			ptr := b.CreateGEP(b.ctx.Int8Type(), base, []llvm.Value{llvmOffset}, "")
+			idx := llvm.ConstInt(b.uintptrType, uint64(i), false)
+			ptr := b.CreateGEP(llvmArrayType, base, []llvm.Value{idx}, "")
 
 			// recursively zero any padding bytes in this element
 			b.zeroUndefBytes(typ.Elem(), ptr)