[llvm] [AMDGPU] MCExpr printing helper with KnownBits support (PR #95951)

[Matt Arsenault via llvm-commits]

================
@@ -314,3 +315,142 @@ AMDGPUVariadicMCExpr::createOccupancy(unsigned InitOcc, const MCExpr *NumSGPRs,
                  CreateExpr(InitOcc), NumSGPRs, NumVGPRs},
                 Ctx);
 }
+
+static KnownBits AMDGPUMCExprKnownBits(const MCExpr *Expr, raw_ostream &OS,
+                                       const MCAsmInfo *MAI, unsigned depth) {
+
+  if (depth == 0)
+    return KnownBits(/*BitWidth=*/64);
----------------
arsenm wrote:

Can you do a const BitWidth = 64 and use that throughout instead of commenting on every literal? 

https://github.com/llvm/llvm-project/pull/95951