diff --git a/Core/MIPS/IR/IRFrontend.cpp b/Core/MIPS/IR/IRFrontend.cpp
index e2e5a207ed40..15f01480f3f3 100644
--- a/Core/MIPS/IR/IRFrontend.cpp
+++ b/Core/MIPS/IR/IRFrontend.cpp
@@ -221,7 +221,7 @@ MIPSOpcode IRFrontend::GetOffsetInstruction(int offset) {
 	return Memory::Read_Instruction(GetCompilerPC() + 4 * offset);
 }
 
-void IRFrontend::DoJit(u32 em_address, std::vector<IRInst> &instructions, std::vector<u32> &constants) {
+void IRFrontend::DoJit(u32 em_address, std::vector<IRInst> &instructions, std::vector<u32> &constants, u32 &mipsBytes) {
 	js.cancel = false;
 	js.blockStart = em_address;
 	js.compilerPC = em_address;
@@ -254,6 +254,8 @@ void IRFrontend::DoJit(u32 em_address, std::vector<IRInst> &instructions, std::v
 		}
 	}
 
+	mipsBytes = js.compilerPC - em_address;
+
 	IRWriter simplified;
 	IRWriter *code = &ir;
 	if (!js.hadBreakpoints) {
diff --git a/Core/MIPS/IR/IRFrontend.h b/Core/MIPS/IR/IRFrontend.h
index 0baa04605736..e91c8ec9131b 100644
--- a/Core/MIPS/IR/IRFrontend.h
+++ b/Core/MIPS/IR/IRFrontend.h
@@ -88,7 +88,7 @@ class IRFrontend : public MIPSFrontendInterface {
 	void DoState(PointerWrap &p);
 	bool CheckRounding();  // returns true if we need a do-over
 
-	void DoJit(u32 em_address, std::vector<IRInst> &instructions, std::vector<u32> &constants);
+	void DoJit(u32 em_address, std::vector<IRInst> &instructions, std::vector<u32> &constants, u32 &mipsBytes);
 
 	void EatPrefix() override {
 		js.EatPrefix();
diff --git a/Core/MIPS/IR/IRJit.cpp b/Core/MIPS/IR/IRJit.cpp
index 0ed6b92b8b8e..d02d65d1e7e3 100644
--- a/Core/MIPS/IR/IRJit.cpp
+++ b/Core/MIPS/IR/IRJit.cpp
@@ -85,8 +85,10 @@ void IRJit::Compile(u32 em_address) {
 
 	std::vector<IRInst> instructions;
 	std::vector<u32> constants;
-	frontend_.DoJit(em_address, instructions, constants);
+	u32 mipsBytes;
+	frontend_.DoJit(em_address, instructions, constants, mipsBytes);
 	b->SetInstructions(instructions, constants);
+	b->SetOriginalSize(mipsBytes);
 	b->Finalize(block_num);  // Overwrites the first instruction
 
 	if (frontend_.CheckRounding()) {
@@ -152,8 +154,13 @@ void IRBlockCache::Clear() {
 	blocks_.clear();
 }
 
-void IRBlockCache::InvalidateICache(u32 addess, u32 length) {
-	// TODO
+void IRBlockCache::InvalidateICache(u32 address, u32 length) {
+	// TODO: Could be more efficient.
+	for (int i = 0; i < size_; ++i) {
+		if (blocks_[i].OverlapsRange(address, length)) {
+			blocks_[i].Destroy(i);
+		}
+	}
 }
 
 std::vector<u32> IRBlockCache::SaveAndClearEmuHackOps() {
@@ -217,6 +224,10 @@ void IRBlock::Destroy(int number) {
 	}
 }
 
+bool IRBlock::OverlapsRange(u32 addr, u32 size) {
+	return addr + size > origAddr_ && addr < origAddr_ + origSize_;
+}
+
 MIPSOpcode IRJit::GetOriginalOp(MIPSOpcode op) {
 	IRBlock *b = blocks_.GetBlock(op.encoding & 0xFFFFFF);
 	return b->GetOriginalFirstOp();
diff --git a/Core/MIPS/IR/IRJit.h b/Core/MIPS/IR/IRJit.h
index 3b1a840e718a..97cd4341f6c8 100644
--- a/Core/MIPS/IR/IRJit.h
+++ b/Core/MIPS/IR/IRJit.h
@@ -100,6 +100,10 @@ class IRBlock {
 	bool HasOriginalFirstOp();
 	bool RestoreOriginalFirstOp(int number);
 	bool IsValid() const { return origAddr_ != 0; }
+	void SetOriginalSize(u32 size) {
+		origSize_ = size;
+	}
+	bool OverlapsRange(u32 addr, u32 size);
 
 	void Finalize(int number);
 	void Destroy(int number);
@@ -110,13 +114,14 @@ class IRBlock {
 	u16 numInstructions_;
 	u16 numConstants_;
 	u32 origAddr_;
+	u32 origSize_;
 	MIPSOpcode origFirstOpcode_;
 };
 
 class IRBlockCache {
 public:
 	void Clear();
-	void InvalidateICache(u32 addess, u32 length);
+	void InvalidateICache(u32 address, u32 length);
 	int GetNumBlocks() const { return (int)blocks_.size(); }
 	int AllocateBlock(int emAddr) {
 		blocks_.push_back(IRBlock(emAddr));