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

Walks over the MCExpr and uses KnownBits to deduce whether an expression
is known and if so, prints said known value. Should support the most
common MCExpr cases for AMDGPU metadata.

Author: JanekvO

llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp

@@ -395,12 +395,10 @@ void AMDGPUAsmPrinter::emitCommonFunctionComments(
 SmallString<128> AMDGPUAsmPrinter::getMCExprStr(const MCExpr *Value) {
   SmallString<128> Str;
   raw_svector_ostream OSS(Str);
-  int64_t IVal;
-  if (Value->evaluateAsAbsolute(IVal)) {
-    OSS << static_cast<uint64_t>(IVal);
-  } else {
-    Value->print(OSS, MAI);
-  }
+  auto &Streamer = getTargetStreamer()->getStreamer();
+  auto &Context = Streamer.getContext();
+  const MCExpr *New = foldAMDGPUMCExpr(Value, Context);
+  printAMDGPUMCExpr(New, OSS, MAI);
   return Str;
 }