From 6b7787cd2bc39d396d7f6ab2036256ba6968bad7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Bylica?= <pawel.bylica@imapp.pl>
Date: Tue, 3 Mar 2015 15:26:16 +0100
Subject: [PATCH] Ad-hoc constant fold arithmetic instructions
---
libevmjit/Arith256.cpp | 90 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 88 insertions(+), 2 deletions(-)
diff --git a/libevmjit/Arith256.cpp b/libevmjit/Arith256.cpp
index 220aa6f05..47701462c 100644
--- a/libevmjit/Arith256.cpp
+++ b/libevmjit/Arith256.cpp
@@ -408,18 +408,49 @@ llvm::Function* Arith256::getMulModFunc()
llvm::Value* Arith256::mul(llvm::Value* _arg1, llvm::Value* _arg2)
{
+ if (auto c1 = llvm::dyn_cast<llvm::ConstantInt>(_arg1))
+ {
+ if (auto c2 = llvm::dyn_cast<llvm::ConstantInt>(_arg2))
+ return Constant::get(c1->getValue() * c2->getValue());
+ }
+
return createCall(getMulFunc(), {_arg1, _arg2});
}
std::pair<llvm::Value*, llvm::Value*> Arith256::div(llvm::Value* _arg1, llvm::Value* _arg2)
{
- auto div = m_builder.CreateExtractValue(createCall(getDivFunc(Type::Word), {_arg1, _arg2}), 0, "div");
- auto mod = m_builder.CreateExtractValue(createCall(getDivFunc(Type::Word), {_arg1, _arg2}), 1, "mod");
+ 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");
+ auto mod = m_builder.CreateExtractValue(r, 1, "mod");
return std::make_pair(div, mod);
}
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);
+ }
+ }
+
auto xIsNeg = m_builder.CreateICmpSLT(_x, Constant::get(0));
auto xNeg = m_builder.CreateSub(Constant::get(0), _x);
auto xAbs = m_builder.CreateSelect(xIsNeg, xNeg, _x);
@@ -443,16 +474,71 @@ std::pair<llvm::Value*, llvm::Value*> Arith256::sdiv(llvm::Value* _x, llvm::Valu
llvm::Value* Arith256::exp(llvm::Value* _arg1, llvm::Value* _arg2)
{
+ // while (e != 0) {
+ // if (e % 2 == 1)
+ // r *= b;
+ // b *= b;
+ // e /= 2;
+ // }
+
+ if (auto c1 = llvm::dyn_cast<llvm::ConstantInt>(_arg1))
+ {
+ if (auto c2 = llvm::dyn_cast<llvm::ConstantInt>(_arg2))
+ {
+ auto b = c1->getValue();
+ auto e = c2->getValue();
+ auto r = llvm::APInt{256, 1};
+ while (e != 0)
+ {
+ if (e[0])
+ r *= b;
+ b *= b;
+ e = e.lshr(1);
+ }
+ return Constant::get(r);
+ }
+ }
+
return createCall(getExpFunc(), {_arg1, _arg2});
}
llvm::Value* Arith256::addmod(llvm::Value* _arg1, llvm::Value* _arg2, llvm::Value* _arg3)
{
+ if (auto c1 = llvm::dyn_cast<llvm::ConstantInt>(_arg1))
+ {
+ if (auto c2 = llvm::dyn_cast<llvm::ConstantInt>(_arg2))
+ {
+ if (auto c3 = llvm::dyn_cast<llvm::ConstantInt>(_arg3))
+ {
+ if (!c3->getValue())
+ return Constant::get(0);
+ auto s = c1->getValue().zext(256+64) + c2->getValue().zext(256+64);
+ auto r = s.urem(c3->getValue().zext(256+64)).trunc(256);
+ return Constant::get(r);
+ }
+ }
+ }
+
return createCall(getAddModFunc(), {_arg1, _arg2, _arg3});
}
llvm::Value* Arith256::mulmod(llvm::Value* _arg1, llvm::Value* _arg2, llvm::Value* _arg3)
{
+ if (auto c1 = llvm::dyn_cast<llvm::ConstantInt>(_arg1))
+ {
+ if (auto c2 = llvm::dyn_cast<llvm::ConstantInt>(_arg2))
+ {
+ if (auto c3 = llvm::dyn_cast<llvm::ConstantInt>(_arg3))
+ {
+ if (!c3->getValue())
+ return Constant::get(0);
+ auto p = c1->getValue().zext(512) * c2->getValue().zext(512);
+ auto r = p.urem(c3->getValue().zext(512)).trunc(256);
+ return Constant::get(r);
+ }
+ }
+ }
+
return createCall(getMulModFunc(), {_arg1, _arg2, _arg3});
}