From 2acbd7ddc0cee21295a1df5416860abb0fdf936f Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Thu, 22 Dec 2011 03:15:35 +0000
Subject: [PATCH] Fix APInt::rotl and APInt::rotr so that they work correctly.
Found while writing some code that tried to use them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147134 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Support/APInt.cpp | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp
index 143ded920e2..b5411bec9d4 100644
--- a/lib/Support/APInt.cpp
+++ b/lib/Support/APInt.cpp
@@ -1338,14 +1338,10 @@ APInt APInt::rotl(const APInt &rotateAmt) const {
}
APInt APInt::rotl(unsigned rotateAmt) const {
+ rotateAmt %= BitWidth;
if (rotateAmt == 0)
return *this;
- // Don't get too fancy, just use existing shift/or facilities
- APInt hi(*this);
- APInt lo(*this);
- hi.shl(rotateAmt);
- lo.lshr(BitWidth - rotateAmt);
- return hi | lo;
+ return shl(rotateAmt) | lshr(BitWidth - rotateAmt);
}
APInt APInt::rotr(const APInt &rotateAmt) const {
@@ -1353,14 +1349,10 @@ APInt APInt::rotr(const APInt &rotateAmt) const {
}
APInt APInt::rotr(unsigned rotateAmt) const {
+ rotateAmt %= BitWidth;
if (rotateAmt == 0)
return *this;
- // Don't get too fancy, just use existing shift/or facilities
- APInt hi(*this);
- APInt lo(*this);
- lo.lshr(rotateAmt);
- hi.shl(BitWidth - rotateAmt);
- return hi | lo;
+ return lshr(rotateAmt) | shl(BitWidth - rotateAmt);
}
// Square Root - this method computes and returns the square root of "this".
--
2.34.1