[llvm] [AMDGPU] Add AMDGPU specific variadic operation MCExprs (PR #82022)

[Pierre van Houtryve via llvm-commits]

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@@ -8130,6 +8132,53 @@ void AMDGPUAsmParser::onBeginOfFile() {
     getTargetStreamer().EmitDirectiveAMDGCNTarget();
 }
 
+/// Parse AMDGPU specific expressions.
+///
+///  expr ::= or(expr, ...) |
+///           max(expr, ...)
+///
+bool AMDGPUAsmParser::parsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
+  using AGVK = AMDGPUVariadicMCExpr::AMDGPUVariadicKind;
+
+  auto parseVariadicExpr = [&](AGVK Kind, const MCExpr *&res, SMLoc &EndLoc) {
+    std::vector<const MCExpr *> Exprs;
+    while (true) {
+      if (isToken(AsmToken::RParen)) {
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Pierre-vh wrote:

`trySkipToken` instead of `isToken` + `lex`?

https://github.com/llvm/llvm-project/pull/82022