[llvm] [MC] Fix operator++ for various MCRegister iterators (PR #81250)

[Jay Foad via llvm-commits]

https://github.com/jayfoad created https://github.com/llvm/llvm-project/pull/81250

Return *this from operator++. NFC, this just allows using ++Iter in
an expression in future patches.


>From e3e07b0d9c8578422710798391411892d5e30543 Mon Sep 17 00:00:00 2001
From: Jay Foad <jay.foad at amd.com>
Date: Fri, 9 Feb 2024 13:49:15 +0000
Subject: [PATCH] [MC] Fix operator++ for various MCRegister iterators

Return *this from operator++. NFC, this just allows using ++Iter in
an expression in future patches.
---
 llvm/include/llvm/MC/MCRegisterInfo.h | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/MC/MCRegisterInfo.h b/llvm/include/llvm/MC/MCRegisterInfo.h
index e52f0a4ff86edf..fb4d11ec1d4d16 100644
--- a/llvm/include/llvm/MC/MCRegisterInfo.h
+++ b/llvm/include/llvm/MC/MCRegisterInfo.h
@@ -572,9 +572,10 @@ class MCSubRegIndexIterator {
   bool isValid() const { return SRIter.isValid(); }
 
   /// Moves to the next position.
-  void operator++() {
+  MCSubRegIndexIterator &operator++() {
     ++SRIter;
     ++SRIndex;
+    return *this;
   }
 };
 
@@ -688,9 +689,10 @@ class MCRegUnitMaskIterator {
   bool isValid() const { return RUIter.isValid(); }
 
   /// Moves to the next position.
-  void operator++() {
+  MCRegUnitMaskIterator &operator++() {
     ++MaskListIter;
     ++RUIter;
+    return *this;
   }
 };
 
@@ -728,10 +730,11 @@ class MCRegUnitRootIterator {
   }
 
   /// Preincrement to move to the next root register.
-  void operator++() {
+  MCRegUnitRootIterator &operator++() {
     assert(isValid() && "Cannot move off the end of the list.");
     Reg0 = Reg1;
     Reg1 = 0;
+    return *this;
   }
 };
 
@@ -788,10 +791,11 @@ class MCRegAliasIterator {
     }
   }
 
-  void operator++() {
+  MCRegAliasIterator &operator++() {
     assert(isValid() && "Cannot move off the end of the list.");
     do advance();
     while (!IncludeSelf && isValid() && *SI == Reg);
+    return *this;
   }
 };