From e272deed7b821976c4ebfe903807dff4f5e852a5 Mon Sep 17 00:00:00 2001 From: Cameron Zwarich Date: Sun, 9 Jan 2011 10:32:30 +0000 Subject: [PATCH] Add an informative comment. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123114 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/StrongPHIElimination.cpp | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp index 5c70423ccec..94a86f24fbf 100644 --- a/lib/CodeGen/StrongPHIElimination.cpp +++ b/lib/CodeGen/StrongPHIElimination.cpp @@ -89,7 +89,15 @@ namespace { /// Add a register in a new congruence class containing only itself. void addReg(unsigned); - /// Join the congruence classes of two registers. + /// Join the congruence classes of two registers. This function is biased + /// towards the left argument, i.e. after + /// + /// addReg(r2); + /// unionRegs(r1, r2); + /// + /// the leader of the unioned congruence class is the same as the leader of + /// r1's congruence class prior to the union. This is actually relied upon + /// in the copy insertion code. void unionRegs(unsigned, unsigned); /// Get the color of a register. The color is 0 if the register has been -- 2.34.1