[llvm] [CodeGenPrepare] Resolve TODO: Treat disjoint-or as an add (PR #88667)

[via llvm-commits]

https://github.com/AtariDreams updated https://github.com/llvm/llvm-project/pull/88667

>From 93eaab9300a947df86edce630ae1c83f34956ade Mon Sep 17 00:00:00 2001
From: Rose <gfunni234 at gmail.com>
Date: Sun, 14 Apr 2024 12:31:10 -0400
Subject: [PATCH] [CodeGenPrepare] Resolve TODO: Treat disjoint-or as an add

Because we can treat Or-disjoint as an add, this allows for better codegen preparation.
---
 llvm/lib/CodeGen/CodeGenPrepare.cpp | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 22dbb3198a9f17..64faa4d018578c 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -4339,6 +4339,8 @@ static bool MightBeFoldableInst(Instruction *I) {
   case Instruction::IntToPtr:
     // We know the input is intptr_t, so this is foldable.
     return true;
+  case Instruction::Or:
+    return cast<PossiblyDisjointInst>(I)->isDisjoint();
   case Instruction::Add:
     return true;
   case Instruction::Mul:
@@ -4851,6 +4853,11 @@ bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode,
       return matchAddr(AddrInst->getOperand(0), Depth);
     return false;
   }
+  case Instruction::Or:
+    // We can handle OR iff it can be treated as an add.
+    if (!cast<PossiblyDisjointInst>(AddrInst)->isDisjoint())
+      break;
+    [[fallthrough]];
   case Instruction::Add: {
     // Check to see if we can merge in one operand, then the other.  If so, we
     // win.
@@ -4891,9 +4898,6 @@ bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode,
     TPT.rollback(LastKnownGood);
     break;
   }
-  // case Instruction::Or:
-  //  TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
-  // break;
   case Instruction::Mul:
   case Instruction::Shl: {
     // Can only handle X*C and X << C.