From 60099e5005aa4f67cde989aaee46711eb511c4c2 Mon Sep 17 00:00:00 2001
From: Robert O'Callahan <rocallahan@google.com>
Date: Fri, 29 Aug 2025 03:09:19 +0000
Subject: [PATCH] Make Const::as_bool and Const::as_int work with packed bits
 without decaying to vector<State>

---
 kernel/rtlil.cc                | 33 ++++++++++++++++++++++++---------
 tests/unit/kernel/rtlilTest.cc | 11 +++++++++++
 2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 243098d54..a74b92f9d 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -383,7 +383,13 @@ std::vector<RTLIL::State> RTLIL::Const::to_bits() const
 
 bool RTLIL::Const::as_bool() const
 {
-	bitvectorize_internal();
+	if (is_str()) {
+		for (char ch : get_str())
+			if (ch != 0)
+				return true;
+		return false;
+	}
+
 	bitvectype& bv = get_bits();
 	for (size_t i = 0; i < bv.size(); i++)
 		if (bv[i] == State::S1)
@@ -393,15 +399,24 @@ bool RTLIL::Const::as_bool() const
 
 int RTLIL::Const::as_int(bool is_signed) const
 {
-	bitvectorize_internal();
-	bitvectype& bv = get_bits();
 	int32_t ret = 0;
-	for (size_t i = 0; i < bv.size() && i < 32; i++)
+	if (is_str()) {
+		const std::string& s = get_str();
+		int size = GetSize(s);
+		for (int i = std::min(4, size); i > 0; i--)
+			ret |= static_cast<unsigned char>(s[size - i]) << ((i - 1) * 8);
+		if (is_signed && size > 0 && size < 4 && (s[0] & 0x80))
+			ret |= -1 << size*8;
+		return ret;
+	}
+
+	const bitvectype& bv = get_bits();
+	int significant_bits = std::min(GetSize(bv), 32);
+	for (int i = 0; i < significant_bits; i++)
 		if (bv[i] == State::S1)
 			ret |= 1 << i;
-	if (is_signed && bv.back() == State::S1)
-		for (size_t i = bv.size(); i < 32; i++)
-			ret |= 1 << i;
+	if (is_signed && significant_bits > 0 && significant_bits < 32 && bv.back() == State::S1 )
+		ret |= -1 << significant_bits;
 	return ret;
 }
 
@@ -421,7 +436,7 @@ bool RTLIL::Const::convertible_to_int(bool is_signed) const
 	if (size == 32) {
 		if (is_signed)
 			return true;
-		return get_bits().at(31) != State::S1;
+		return back() != State::S1;
 	}
 
 	return false;
@@ -442,7 +457,7 @@ int RTLIL::Const::as_int_saturating(bool is_signed) const
 
 		const auto min_size = get_min_size(is_signed);
 		log_assert(min_size > 0);
-		const auto neg = get_bits().at(min_size - 1);
+		const auto neg = (*this)[min_size - 1];
 		return neg ? std::numeric_limits<int>::min() : std::numeric_limits<int>::max();
 	}
 	return as_int(is_signed);
diff --git a/tests/unit/kernel/rtlilTest.cc b/tests/unit/kernel/rtlilTest.cc
index 0b7fbfd37..99ddf44cc 100644
--- a/tests/unit/kernel/rtlilTest.cc
+++ b/tests/unit/kernel/rtlilTest.cc
@@ -92,12 +92,14 @@ namespace RTLIL {
 			Const c(0x12345678);
 			EXPECT_TRUE(c.is_str());
 			EXPECT_EQ(c.as_int(), 0x12345678);
+			EXPECT_TRUE(c.is_str());
 		}
 
 		{
 			Const c(0xab, 8);
 			EXPECT_TRUE(c.is_str());
 			EXPECT_EQ(c.as_int(), 0xab);
+			EXPECT_TRUE(c.is_str());
 		}
 
 		{
@@ -105,6 +107,7 @@ namespace RTLIL {
 			EXPECT_TRUE(c.is_str());
 			EXPECT_EQ(c.as_int(), 0x12345678);
 			EXPECT_EQ(c[79], S0);
+			EXPECT_TRUE(c.is_str());
 		}
 
 		{
@@ -112,6 +115,14 @@ namespace RTLIL {
 			EXPECT_TRUE(c.is_str());
 			EXPECT_EQ(c.as_int(), -1);
 			EXPECT_EQ(c[79], S1);
+			EXPECT_TRUE(c.is_str());
+		}
+
+		{
+			Const c(1 << 24);
+			EXPECT_TRUE(c.is_str());
+			EXPECT_TRUE(c.as_bool());
+			EXPECT_TRUE(c.is_str());
 		}
 	}