[mlir][openacc] Fix num_gang parser (#78792)

Nb of operand per segment is not correctly computed.

Author: clementval

mlir/lib/Dialect/OpenACC/IR/OpenACC.cpp

@@ -818,6 +818,7 @@ static ParseResult parseNumGangs(
     if (failed(parser.parseLBrace()))
       return failure();
 
+    int32_t crtOperandsSize = operands.size();
     if (failed(parser.parseCommaSeparatedList(
             mlir::AsmParser::Delimiter::None, [&]() {
               if (parser.parseOperand(operands.emplace_back()) ||
@@ -826,8 +827,7 @@ static ParseResult parseNumGangs(
               return success();
             })))
       return failure();
-
-    seg.push_back(operands.size());
+    seg.push_back(operands.size() - crtOperandsSize);
 
     if (failed(parser.parseRBrace()))
       return failure();

mlir/test/Dialect/OpenACC/ops.mlir

@@ -1878,3 +1878,12 @@ func.func @acc_atomic_capture(%v: memref<i32>, %x: memref<i32>, %expr: i32) {
 
   return
 }
+
+// -----
+
+%c2 = arith.constant 2 : i32
+%c1 = arith.constant 1 : i32
+acc.parallel num_gangs({%c2 : i32} [#acc.device_type<default>], {%c1 : i32, %c1 : i32, %c1 : i32} [#acc.device_type<nvidia>]) {
+}
+
+// CHECK: acc.parallel num_gangs({%c2{{.*}} : i32} [#acc.device_type<default>], {%c1{{.*}} : i32, %c1{{.*}} : i32, %c1{{.*}} : i32} [#acc.device_type<nvidia>])