From 5412b20b47fa05849adfe80ffdeb9e63a817da7b Mon Sep 17 00:00:00 2001
From: Gabe Black <gabe.black@gmail.com>
Date: Fri, 23 Jul 2021 21:29:25 -0700
Subject: [PATCH] base: Use if constexpr to simplify the reverseBits function.

Handle the sizeof(T) == 1 special case within the function using if
constexpr, instead of having two functions.

Change-Id: Idce63e18c77d2f7cc59d86c19f42d57ccdbefe5c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/48504
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>
---
 src/base/bitfield.hh | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/src/base/bitfield.hh b/src/base/bitfield.hh
index 30cc952d09..b2f3d6327b 100644
--- a/src/base/bitfield.hh
+++ b/src/base/bitfield.hh
@@ -232,26 +232,23 @@ replaceBits(T& val, unsigned bit, B bit_val)
  * @ingroup api_bitfield
  */
 template <class T>
-std::enable_if_t<std::is_integral<T>::value && sizeof(T) != 1, T>
+std::enable_if_t<std::is_integral_v<T>, T>
 reverseBits(T val, size_t size=sizeof(T))
 {
     assert(size <= sizeof(T));
 
-    T output = {};
-    for (size_t byte = 0; byte < size; byte++) {
-        output = (output << 8) | reverseBitsLookUpTable[val & mask(8)];
-        val >>= 8;
+    if constexpr (sizeof(T) == 1) {
+        return reverseBitsLookUpTable[val];
+    } else {
+        T output = {};
+
+        for (size_t byte = 0; byte < size; byte++) {
+            output = (output << 8) | reverseBitsLookUpTable[val & mask(8)];
+            val >>= 8;
+        }
+
+        return output;
     }
-
-    return output;
-}
-
-template <class T>
-std::enable_if_t<std::is_integral<T>::value && sizeof(T) == 1, T>
-reverseBits(T val, size_t size=sizeof(T))
-{
-    assert(size == 1);
-    return reverseBitsLookUpTable[val];
 }
 
 /**