[llvm] [DAGCombiner][AMDGPU] Track signedness in ByteProviders (PR #65995)

[Matt Arsenault via llvm-commits]

================
@@ -10576,7 +10584,7 @@ calculateSrcByte(const SDValue Op, uint64_t DestByte, uint64_t SrcIndex = 0,
 // performed. \p StartingIndex is the originally requested byte of the Or
 static const std::optional<ByteProvider<SDValue>>
 calculateByteProvider(const SDValue &Op, unsigned Index, unsigned Depth,
-                      unsigned StartingIndex = 0) {
+                      unsigned StartingIndex = 0, bool IsSigned = 0) {
----------------
arsenm wrote:

= false

https://github.com/llvm/llvm-project/pull/65995