[llvm-branch-commits] [llvm] release/22.x: MIPS: Fix unsigned compare with zero in MipsSEInstrInfo::copyPhysReg (#179866) (PR #179893)

[via llvm-branch-commits]

https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/179893

Backport 209ff8bf06dd12becd79c1ebb01612c021e19f6c

Requested by: @wzssyqa

>From 8175b4d49cd3f312d18368af7970995d47a56485 Mon Sep 17 00:00:00 2001
From: YunQiang Su <syq at debian.org>
Date: Thu, 5 Feb 2026 17:09:22 +0800
Subject: [PATCH] MIPS: Fix unsigned compare with zero in
 MipsSEInstrInfo::copyPhysReg (#179866)
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SrcRegOff >= 0 is not needed at all for unsigned.

This fixes the warning:
```
llvm/lib/Target/Mips/MipsSEInstrInfo.cpp: In member function ‘virtual void llvm::MipsSEInstrInfo::copyPhysReg(llvm::MachineBasicBlock&, llvm::MachineBasicBlock::iterator, const llvm::DebugLoc&, llvm::Register, llvm::Register, bool, bool, bool) const’:
llvm/lib/Target/Mips/MipsSEInstrInfo.cpp:245:48: warning: comparison of unsigned expression in ‘>= 0’ is always true [-Wtype-limits]
  245 |       if (SrcRegOff == DestRegOff && SrcRegOff >= 0 && SrcRegOff <= 31)
      |                                      ~~~~~~~~~~^~~~
llvm/lib/Target/Mips/MipsSEInstrInfo.cpp:256:48: warning: comparison of unsigned expression in ‘>= 0’ is always true [-Wtype-limits]
  256 |       if (SrcRegOff == DestRegOff && SrcRegOff >= 0 && SrcRegOff <= 31)
```

(cherry picked from commit 209ff8bf06dd12becd79c1ebb01612c021e19f6c)
---
 llvm/lib/Target/Mips/MipsSEInstrInfo.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp b/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
index 4a92b1ffc4cf9..90f2996e7f93e 100644
--- a/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsSEInstrInfo.cpp
@@ -242,7 +242,7 @@ void MipsSEInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
       Opc = Mips::FMOV_D64;
       unsigned DestRegOff = DestReg.id() - Mips::D0_64;
       unsigned SrcRegOff = SrcReg.id() - Mips::F0;
-      if (SrcRegOff == DestRegOff && SrcRegOff >= 0 && SrcRegOff <= 31)
+      if (SrcRegOff == DestRegOff && SrcRegOff <= 31)
         return;
     }
   } else if (Opc == 0 && Mips::FGR32RegClass.contains(DestReg) &&
@@ -253,7 +253,7 @@ void MipsSEInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
       Opc = Mips::FMOV_D32;
       unsigned DestRegOff = DestReg.id() - Mips::F0;
       unsigned SrcRegOff = SrcReg.id() - Mips::D0_64;
-      if (SrcRegOff == DestRegOff && SrcRegOff >= 0 && SrcRegOff <= 31)
+      if (SrcRegOff == DestRegOff && SrcRegOff <= 31)
         return;
     }
   }