diff --git a/crates/codegen/src/yul/isel/inst_order.rs b/crates/codegen/src/yul/isel/inst_order.rs
index b6e5317e77..96028c1bcc 100644
--- a/crates/codegen/src/yul/isel/inst_order.rs
+++ b/crates/codegen/src/yul/isel/inst_order.rs
@@ -27,6 +27,7 @@ pub(super) struct InstSerializer<'a> {
     cfg: ControlFlowGraph,
     loop_tree: LoopTree,
     df: DFSet,
+    domtree: DomTree,
     pd_tree: PostDomTree,
     scope: Option<Scope>,
 }
@@ -44,6 +45,7 @@ impl<'a> InstSerializer<'a> {
             cfg,
             loop_tree,
             df,
+            domtree,
             pd_tree,
             scope: None,
         }
@@ -125,7 +127,6 @@ impl<'a> InstSerializer<'a> {
         let mut else_body = vec![];
 
         self.enter_if_scope(merge_block);
-
         let mut serialize_dest =
             |dest_info, body: &mut Vec<StructuralInst>, merge_block| match dest_info {
                 TerminatorInfo::Break => body.push(StructuralInst::Break),
@@ -251,25 +252,77 @@ impl<'a> InstSerializer<'a> {
         &self,
         block: BasicBlockId,
         cond: ValueId,
-        then: BasicBlockId,
-        else_: BasicBlockId,
+        then_bb: BasicBlockId,
+        else_bb: BasicBlockId,
     ) -> TerminatorInfo {
-        let then = Box::new(self.analyze_dest(then));
-        let else_ = Box::new(self.analyze_dest(else_));
+        let then = Box::new(self.analyze_dest(then_bb));
+        let else_ = Box::new(self.analyze_dest(else_bb));
 
-        let merge_block = match self.pd_tree.post_idom(block) {
-            PostIDom::Block(block) => {
-                if let Some(lp) = self.scope.as_ref().and_then(Scope::loop_recursive) {
-                    if self.loop_tree.is_block_in_loop(block, lp) {
-                        Some(block)
-                    } else {
-                        None
-                    }
+        let cand_for_merge_bb = |bb| {
+            if self.domtree.dominates(bb, block) {
+                return None;
+            }
+
+            // a block `cand` can be a candidate of a `merge` block iff
+            // 1. `cand` is a dominance frontier of `bb`.
+            // 2. `cand` is NOT a dominator of `bb`.
+            // 3. `cand` is NOT a "merge" block of parent `if`.
+            // 4. `cand` is NOT a "loop_exit" block of parent `loop`.
+            let mut cands = self.df.frontiers(bb)?.filter(|cand| {
+                !self.domtree.dominates(*cand, bb)
+                    && Some(*cand)
+                        != self
+                            .scope
+                            .as_ref()
+                            .and_then(Scope::if_merge_block_recursive)
+                    && Some(*cand) != self.scope.as_ref().and_then(Scope::loop_exit_recursive)
+            });
+
+            let cand = cands.next();
+            // Assert the number of candidates is at most one.
+            debug_assert!(cands.next().is_none());
+            cand
+        };
+
+        let merge_block = match (cand_for_merge_bb(then_bb), cand_for_merge_bb(else_bb)) {
+            (Some(then_cand), Some(else_cand)) => {
+                if then_cand == else_cand {
+                    Some(then_cand)
                 } else {
-                    Some(block)
+                    None
                 }
             }
-            _ => None,
+
+            (Some(cand), None) => {
+                if cand == else_bb {
+                    Some(cand)
+                } else {
+                    None
+                }
+            }
+
+            (None, Some(cand)) => {
+                if cand == then_bb {
+                    Some(cand)
+                } else {
+                    None
+                }
+            }
+
+            (None, None) => match self.pd_tree.post_idom(block) {
+                PostIDom::Block(block) => {
+                    if let Some(lp) = self.scope.as_ref().and_then(Scope::loop_recursive) {
+                        if self.loop_tree.is_block_in_loop(block, lp) {
+                            Some(block)
+                        } else {
+                            None
+                        }
+                    } else {
+                        Some(block)
+                    }
+                }
+                _ => None,
+            },
         };
 
         TerminatorInfo::If {
@@ -291,7 +344,7 @@ impl<'a> InstSerializer<'a> {
                     TerminatorInfo::Continue
                 } else if Some(dest) == scope.loop_exit_recursive() {
                     TerminatorInfo::Break
-                } else if Some(dest) == scope.if_merge_block() {
+                } else if Some(dest) == scope.if_merge_block_recursive() {
                     TerminatorInfo::ToMergeBlock
                 } else {
                     TerminatorInfo::FallThrough(dest)
@@ -355,6 +408,15 @@ impl Scope {
             _ => None,
         }
     }
+
+    fn if_merge_block_recursive(&self) -> Option<BasicBlockId> {
+        match self.kind {
+            ScopeKind::If {
+                merge_block: Some(merge_block),
+            } => Some(merge_block),
+            _ => self.parent.as_ref()?.if_merge_block_recursive(),
+        }
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -387,37 +449,40 @@ mod tests {
     }
 
     fn expect_if(
-        inst: StructuralInst,
+        insts: &mut impl Iterator<Item = StructuralInst>,
     ) -> (
         impl Iterator<Item = StructuralInst>,
         impl Iterator<Item = StructuralInst>,
     ) {
-        match inst {
+        match insts.next().unwrap() {
             StructuralInst::If { then, else_, .. } => (then.into_iter(), else_.into_iter()),
             _ => panic!("expect if inst"),
         }
     }
 
-    fn expect_for(inst: StructuralInst) -> impl Iterator<Item = StructuralInst> {
-        match inst {
+    fn expect_for(
+        insts: &mut impl Iterator<Item = StructuralInst>,
+    ) -> impl Iterator<Item = StructuralInst> {
+        match insts.next().unwrap() {
             StructuralInst::For { body } => body.into_iter(),
             _ => panic!("expect if inst"),
         }
     }
 
-    fn expect_break(inst: StructuralInst) {
-        assert!(matches!(inst, StructuralInst::Break))
+    fn expect_break(insts: &mut impl Iterator<Item = StructuralInst>) {
+        assert!(matches!(insts.next().unwrap(), StructuralInst::Break))
     }
 
-    fn expect_continue(inst: StructuralInst) {
-        assert!(matches!(inst, StructuralInst::Continue))
+    fn expect_continue(insts: &mut impl Iterator<Item = StructuralInst>) {
+        assert!(matches!(insts.next().unwrap(), StructuralInst::Continue))
     }
 
-    fn expect_return(func: &FunctionBody, inst: &StructuralInst) {
+    fn expect_return(func: &FunctionBody, insts: &mut impl Iterator<Item = StructuralInst>) {
+        let inst = insts.next().unwrap();
         match inst {
             StructuralInst::Inst(inst) => {
                 assert!(matches!(
-                    func.store.inst_data(*inst).kind,
+                    func.store.inst_data(inst).kind,
                     InstKind::Return { .. }
                 ))
             }
@@ -425,6 +490,10 @@ mod tests {
         }
     }
 
+    fn expect_end(insts: &mut impl Iterator<Item = StructuralInst>) {
+        assert!(insts.next().is_none())
+    }
+
     #[test]
     fn if_non_merge() {
         // +------+     +-------+
@@ -456,13 +525,13 @@ mod tests {
         let mut func = builder.build();
         let mut order = serialize_func_body(&mut func);
 
-        let (mut then, mut else_) = expect_if(order.next().unwrap());
-        expect_return(&func, &then.next().unwrap());
-        assert!(then.next().is_none());
-        expect_return(&func, &else_.next().unwrap());
-        assert!(else_.next().is_none());
+        let (mut then, mut else_) = expect_if(&mut order);
+        expect_return(&func, &mut then);
+        expect_end(&mut then);
+        expect_return(&func, &mut else_);
+        expect_end(&mut else_);
 
-        assert!(order.next().is_none());
+        expect_end(&mut order);
     }
 
     #[test]
@@ -506,12 +575,76 @@ mod tests {
         let mut func = builder.build();
         let mut order = serialize_func_body(&mut func);
 
-        let (mut then, mut else_) = expect_if(order.next().unwrap());
-        assert!(then.next().is_none());
-        assert!(else_.next().is_none());
+        let (mut then, mut else_) = expect_if(&mut order);
+        expect_end(&mut then);
+        expect_end(&mut else_);
+
+        expect_return(&func, &mut order);
+        expect_end(&mut order);
+    }
+
+    #[test]
+    fn nested_if() {
+        //             +-----+
+        //             | bb0 | -+
+        //             +-----+  |
+        //               |      |
+        //               |      |
+        //               v      |
+        // +-----+     +-----+  |
+        // | bb3 | <-- | bb1 |  |
+        // +-----+     +-----+  |
+        //               |      |
+        //               |      |
+        //               v      |
+        //             +-----+  |
+        //             | bb4 |  |
+        //             +-----+  |
+        //               |      |
+        //               |      |
+        //               v      |
+        //             +-----+  |
+        //             | bb2 | <+
+        //             +-----+
+        let mut builder = body_builder();
+
+        let bb1 = builder.make_block();
+        let bb2 = builder.make_block();
+        let bb3 = builder.make_block();
+        let bb4 = builder.make_block();
+
+        let dummy_ty = TypeId(0);
+        let v0 = builder.make_imm_from_bool(true, dummy_ty);
+        let unit = builder.make_unit(dummy_ty);
+
+        builder.branch(v0, bb1, bb2, SourceInfo::dummy());
+
+        builder.move_to_block(bb1);
+        builder.branch(v0, bb3, bb4, SourceInfo::dummy());
+
+        builder.move_to_block(bb3);
+        builder.ret(unit, SourceInfo::dummy());
+
+        builder.move_to_block(bb4);
+        builder.jump(bb2, SourceInfo::dummy());
+
+        builder.move_to_block(bb2);
+        builder.ret(unit, SourceInfo::dummy());
+
+        let mut func = builder.build();
+        let mut order = serialize_func_body(&mut func);
+
+        let (mut then1, mut else2) = expect_if(&mut order);
+        expect_end(&mut else2);
+
+        let (mut then3, mut else4) = expect_if(&mut then1);
+        expect_end(&mut then1);
+        expect_return(&func, &mut then3);
+        expect_end(&mut then3);
+        expect_end(&mut else4);
 
-        expect_return(&func, &order.next().unwrap());
-        assert!(order.next().is_none());
+        expect_return(&func, &mut order);
+        expect_end(&mut order);
     }
 
     #[test]
@@ -561,22 +694,22 @@ mod tests {
         let mut func = builder.build();
         let mut order = serialize_func_body(&mut func);
 
-        let (mut lp, mut empty) = expect_if(order.next().unwrap());
+        let (mut lp, mut empty) = expect_if(&mut order);
 
-        let mut body = expect_for(lp.next().unwrap());
-        let (mut continue_, mut break_) = expect_if(body.next().unwrap());
-        assert!(body.next().is_none());
+        let mut body = expect_for(&mut lp);
+        let (mut continue_, mut break_) = expect_if(&mut body);
+        expect_end(&mut body);
 
-        expect_continue(continue_.next().unwrap());
-        assert!(continue_.next().is_none());
+        expect_continue(&mut continue_);
+        expect_end(&mut continue_);
 
-        expect_break(break_.next().unwrap());
-        assert!(break_.next().is_none());
+        expect_break(&mut break_);
+        expect_end(&mut break_);
 
-        assert!(empty.next().is_none());
+        expect_end(&mut empty);
 
-        expect_return(&func, &order.next().unwrap());
-        assert!(order.next().is_none());
+        expect_return(&func, &mut order);
+        expect_end(&mut order);
     }
 
     #[test]
@@ -630,27 +763,27 @@ mod tests {
         let mut func = builder.build();
         let mut order = serialize_func_body(&mut func);
 
-        let (mut lp, mut empty) = expect_if(order.next().unwrap());
-        assert!(empty.next().is_none());
+        let (mut lp, mut empty) = expect_if(&mut order);
+        expect_end(&mut empty);
 
-        let mut body = expect_for(lp.next().unwrap());
+        let mut body = expect_for(&mut lp);
 
-        let (mut continue_, mut empty) = expect_if(body.next().unwrap());
-        expect_continue(continue_.next().unwrap());
-        assert!(continue_.next().is_none());
-        assert!(empty.next().is_none());
+        let (mut continue_, mut empty) = expect_if(&mut body);
+        expect_continue(&mut continue_);
+        expect_end(&mut continue_);
+        expect_end(&mut empty);
 
-        let (mut continue_, mut break_) = expect_if(body.next().unwrap());
-        expect_continue(continue_.next().unwrap());
-        assert!(continue_.next().is_none());
-        expect_break(break_.next().unwrap());
-        assert!(break_.next().is_none());
+        let (mut continue_, mut break_) = expect_if(&mut body);
+        expect_continue(&mut continue_);
+        expect_end(&mut continue_);
+        expect_break(&mut break_);
+        expect_end(&mut break_);
 
-        assert!(body.next().is_none());
-        assert!(lp.next().is_none());
+        expect_end(&mut body);
+        expect_end(&mut lp);
 
-        expect_return(&func, &order.next().unwrap());
-        assert!(order.next().is_none());
+        expect_return(&func, &mut order);
+        expect_end(&mut order);
     }
 
     #[test]
@@ -704,27 +837,27 @@ mod tests {
         let mut func = builder.build();
         let mut order = serialize_func_body(&mut func);
 
-        let (mut lp, mut empty) = expect_if(order.next().unwrap());
-        assert!(empty.next().is_none());
+        let (mut lp, mut empty) = expect_if(&mut order);
+        expect_end(&mut empty);
 
-        let mut body = expect_for(lp.next().unwrap());
+        let mut body = expect_for(&mut lp);
 
-        let (mut break_, mut latch) = expect_if(body.next().unwrap());
-        expect_break(break_.next().unwrap());
-        assert!(break_.next().is_none());
+        let (mut break_, mut latch) = expect_if(&mut body);
+        expect_break(&mut break_);
+        expect_end(&mut break_);
 
-        let (mut continue_, mut break_) = expect_if(latch.next().unwrap());
-        assert!(latch.next().is_none());
-        expect_continue(continue_.next().unwrap());
-        assert!(continue_.next().is_none());
-        expect_break(break_.next().unwrap());
-        assert!(break_.next().is_none());
+        let (mut continue_, mut break_) = expect_if(&mut latch);
+        expect_end(&mut latch);
+        expect_continue(&mut continue_);
+        expect_end(&mut continue_);
+        expect_break(&mut break_);
+        expect_end(&mut break_);
 
-        assert!(body.next().is_none());
-        assert!(lp.next().is_none());
+        expect_end(&mut body);
+        expect_end(&mut lp);
 
-        expect_return(&func, &order.next().unwrap());
-        assert!(order.next().is_none());
+        expect_return(&func, &mut order);
+        expect_end(&mut order);
     }
 
     #[test]
@@ -774,18 +907,18 @@ mod tests {
         let mut func = builder.build();
         let mut order = serialize_func_body(&mut func);
 
-        let mut body = expect_for(order.next().unwrap());
-        let (mut continue_, mut break_) = expect_if(body.next().unwrap());
-        assert!(body.next().is_none());
+        let mut body = expect_for(&mut order);
+        let (mut continue_, mut break_) = expect_if(&mut body);
+        expect_end(&mut body);
 
-        expect_continue(continue_.next().unwrap());
-        assert!(continue_.next().is_none());
+        expect_continue(&mut continue_);
+        expect_end(&mut continue_);
 
-        expect_break(break_.next().unwrap());
-        assert!(break_.next().is_none());
+        expect_break(&mut break_);
+        expect_end(&mut break_);
 
-        expect_return(&func, &order.next().unwrap());
-        assert!(order.next().is_none());
+        expect_return(&func, &mut order);
+        expect_end(&mut order);
     }
 
     #[test]
@@ -821,10 +954,10 @@ mod tests {
         let mut func = builder.build();
         let mut order = serialize_func_body(&mut func);
 
-        let mut body = expect_for(order.next().unwrap());
-        expect_continue(body.next().unwrap());
-        assert!(body.next().is_none());
+        let mut body = expect_for(&mut order);
+        expect_continue(&mut body);
+        expect_end(&mut body);
 
-        assert!(order.next().is_none());
+        expect_end(&mut order);
     }
 }
diff --git a/newsfragments/749.bugfix.md b/newsfragments/749.bugfix.md
new file mode 100644
index 0000000000..3a5bf62aa4
--- /dev/null
+++ b/newsfragments/749.bugfix.md
@@ -0,0 +1,18 @@
+Fix a bug that causes ICE when nested if-statement has multiple exit point.
+
+E.g. the following code would previously crash the compiler but shouldn't:
+```fe
+ pub fn foo(self) {
+    if true {
+        if self.something { 
+            return 
+        }
+    }
+    if true {
+        if self.something { 
+            return 
+        }
+    }
+}
+```
+