From 01a015747e274480fc5ae8d0fab18d89d04ea8b0 Mon Sep 17 00:00:00 2001
From: Rasmus Munk Larsen <rmlarsen@google.com>
Date: Wed, 27 Sep 2023 17:16:13 -0700
Subject: [PATCH 1/2] Speed up RTLIL::Const::decode_string by 1.7x.
---
kernel/rtlil.cc | 33 ++++++++++++++++++++++++---------
1 file changed, 24 insertions(+), 9 deletions(-)
diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 1b57af60a..3663ca864 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -313,18 +313,33 @@ RTLIL::Const RTLIL::Const::from_string(const std::string &str)
std::string RTLIL::Const::decode_string() const
{
- std::string string;
- string.reserve(GetSize(bits)/8);
- for (int i = 0; i < GetSize(bits); i += 8) {
+ const int n = GetSize(bits);
+ const int n_over_8 = n / 8;
+ std::string s;
+ s.reserve(n_over_8);
+ int i = n_over_8 * 8;
+ if (i < n) {
char ch = 0;
- for (int j = 0; j < 8 && i + j < int (bits.size()); j++)
- if (bits[i + j] == RTLIL::State::S1)
+ for (int j = 0; j < (n - i); j++) {
+ if (bits[j + i] == RTLIL::State::S1) {
ch |= 1 << j;
+ }
+ }
if (ch != 0)
- string.append({ch});
+ s.append({ch});
}
- std::reverse(string.begin(), string.end());
- return string;
+ i -= 8;
+ for (; i >= 0; i -= 8) {
+ char ch = 0;
+ for (int j = 0; j < 8; j++) {
+ if (bits[j + i] == RTLIL::State::S1) {
+ ch |= 1 << j;
+ }
+ }
+ if (ch != 0)
+ s.append({ch});
+ }
+ return s;
}
bool RTLIL::Const::is_fully_zero() const
@@ -4044,7 +4059,7 @@ void RTLIL::SigSpec::replace(const RTLIL::SigSpec &pattern, const RTLIL::SigSpec
other->bits_[j] = with.bits_[it->second];
}
}
-
+
other->check();
}
From 12218a4c744cb3877e5d9e78d15b7c2d90667907 Mon Sep 17 00:00:00 2001
From: Rasmus Munk Larsen <rmlarsen@google.com>
Date: Thu, 28 Sep 2023 19:39:09 -0700
Subject: [PATCH 2/2] Unflip i and j.
---
kernel/rtlil.cc | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 3663ca864..9834a0d37 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -321,7 +321,7 @@ std::string RTLIL::Const::decode_string() const
if (i < n) {
char ch = 0;
for (int j = 0; j < (n - i); j++) {
- if (bits[j + i] == RTLIL::State::S1) {
+ if (bits[i + j] == RTLIL::State::S1) {
ch |= 1 << j;
}
}
@@ -332,7 +332,7 @@ std::string RTLIL::Const::decode_string() const
for (; i >= 0; i -= 8) {
char ch = 0;
for (int j = 0; j < 8; j++) {
- if (bits[j + i] == RTLIL::State::S1) {
+ if (bits[i + j] == RTLIL::State::S1) {
ch |= 1 << j;
}
}