diff --git a/hercules_cg/src/cpu.rs b/hercules_cg/src/cpu.rs
index 37bf814d85569a5aa8dd827e2fce17894da5a397..f7fd34db98e3af776f561c094c6c18bd241aa1e5 100644
--- a/hercules_cg/src/cpu.rs
+++ b/hercules_cg/src/cpu.rs
@@ -76,7 +76,7 @@ impl<'a> CPUContext<'a> {
             } else {
                 write!(
                     w,
-                    "define dso_local nonnull noundef {} @{}_{}(",
+                    "define dso_local nonnull noundef nounwind nosync willreturn norecurse {} @{}_{}(",
                     self.get_type(return_type),
                     self.module_name,
                     self.function.name,
@@ -346,7 +346,7 @@ impl<'a> CPUContext<'a> {
                     let offset = offsets[&id].0;
                     write!(
                         body,
-                        "  {} = getelementptr i8, ptr %backing, i64 %dc{}\n",
+                        "  {} = getelementptr inbounds i8, ptr %backing, i64 %dc{}\n",
                         self.get_value(id, false),
                         offset.idx()
                     )?;
@@ -473,11 +473,14 @@ impl<'a> CPUContext<'a> {
 
                 let opcode = match (op, op_ty) {
                     (BinaryOperator::Add, OpTy::Float) => "fadd",
-                    (BinaryOperator::Add, _) => "add",
+                    (BinaryOperator::Add, OpTy::Unsigned) => "add nuw",
+                    (BinaryOperator::Add, OpTy::Signed) => "add nsw",
                     (BinaryOperator::Sub, OpTy::Float) => "fsub",
-                    (BinaryOperator::Sub, _) => "sub",
+                    (BinaryOperator::Sub, OpTy::Unsigned) => "sub nuw",
+                    (BinaryOperator::Sub, OpTy::Signed) => "sub nsw",
                     (BinaryOperator::Mul, OpTy::Float) => "fmul",
-                    (BinaryOperator::Mul, _) => "mul",
+                    (BinaryOperator::Mul, OpTy::Unsigned) => "mul nuw",
+                    (BinaryOperator::Mul, OpTy::Signed) => "mul nsw",
                     (BinaryOperator::Div, OpTy::Float) => "fdiv",
                     (BinaryOperator::Div, OpTy::Unsigned) => "udiv",
                     (BinaryOperator::Div, OpTy::Signed) => "sdiv",
@@ -1005,7 +1008,7 @@ impl<'a> CPUContext<'a> {
         let name = format!("%gep.{}", Self::gen_filler_id());
         write!(
             body,
-            "  {} = getelementptr i8, ptr {}, i64 {}\n",
+            "  {} = getelementptr inbounds i8, ptr {}, i64 {}\n",
             name, ptr, size
         )?;
         Ok(name)