From cc1be11d6c36d1da99af09181bb756b83c9dc54e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Bylica?= <pawel.bylica@imapp.pl>
Date: Thu, 19 Mar 2015 12:07:10 +0100
Subject: [PATCH] Constant folding in div-based operators disabled

There is a bug in LLVM arbitrary precision division algorithm.
---
 evmjit/libevmjit/Arith256.cpp | 46 ++++++++++++++++++-----------------
 1 file changed, 24 insertions(+), 22 deletions(-)

diff --git a/evmjit/libevmjit/Arith256.cpp b/evmjit/libevmjit/Arith256.cpp
index f24626750..e88fda432 100644
--- a/evmjit/libevmjit/Arith256.cpp
+++ b/evmjit/libevmjit/Arith256.cpp
@@ -371,17 +371,18 @@ llvm::Value* Arith256::mul(llvm::Value* _arg1, llvm::Value* _arg2)
 
 std::pair<llvm::Value*, llvm::Value*> Arith256::div(llvm::Value* _arg1, llvm::Value* _arg2)
 {
-	if (auto c1 = llvm::dyn_cast<llvm::ConstantInt>(_arg1))
-	{
-		if (auto c2 = llvm::dyn_cast<llvm::ConstantInt>(_arg2))
-		{
-			if (!c2->getValue())
-				return std::make_pair(Constant::get(0), Constant::get(0));
-			auto div = Constant::get(c1->getValue().udiv(c2->getValue()));
-			auto mod = Constant::get(c1->getValue().urem(c2->getValue()));
-			return std::make_pair(div, mod);
-		}
-	}
+	// FIXME: Disabled because of llvm::APInt::urem bug
+//	if (auto c1 = llvm::dyn_cast<llvm::ConstantInt>(_arg1))
+//	{
+//		if (auto c2 = llvm::dyn_cast<llvm::ConstantInt>(_arg2))
+//		{
+//			if (!c2->getValue())
+//				return std::make_pair(Constant::get(0), Constant::get(0));
+//			auto div = Constant::get(c1->getValue().udiv(c2->getValue()));
+//			auto mod = Constant::get(c1->getValue().urem(c2->getValue()));
+//			return std::make_pair(div, mod);
+//		}
+//	}
 
 	auto r = createCall(getDivFunc(Type::Word), {_arg1, _arg2});
 	auto div =  m_builder.CreateExtractValue(r, 0, "div");
@@ -391,17 +392,18 @@ std::pair<llvm::Value*, llvm::Value*> Arith256::div(llvm::Value* _arg1, llvm::Va
 
 std::pair<llvm::Value*, llvm::Value*> Arith256::sdiv(llvm::Value* _x, llvm::Value* _y)
 {
-	if (auto c1 = llvm::dyn_cast<llvm::ConstantInt>(_x))
-	{
-		if (auto c2 = llvm::dyn_cast<llvm::ConstantInt>(_y))
-		{
-			if (!c2->getValue())
-				return std::make_pair(Constant::get(0), Constant::get(0));
-			auto div = Constant::get(c1->getValue().sdiv(c2->getValue()));
-			auto mod = Constant::get(c1->getValue().srem(c2->getValue()));
-			return std::make_pair(div, mod);
-		}
-	}
+	// FIXME: Disabled because of llvm::APInt::urem bug
+//	if (auto c1 = llvm::dyn_cast<llvm::ConstantInt>(_x))
+//	{
+//		if (auto c2 = llvm::dyn_cast<llvm::ConstantInt>(_y))
+//		{
+//			if (!c2->getValue())
+//				return std::make_pair(Constant::get(0), Constant::get(0));
+//			auto div = Constant::get(c1->getValue().sdiv(c2->getValue()));
+//			auto mod = Constant::get(c1->getValue().srem(c2->getValue()));
+//			return std::make_pair(div, mod);
+//		}
+//	}
 
 	auto xIsNeg = m_builder.CreateICmpSLT(_x, Constant::get(0));
 	auto xNeg = m_builder.CreateSub(Constant::get(0), _x);