Precompiled timestamps.

cpp/src/gandiva/engine.cc

@@ -109,7 +109,6 @@
 #include "gandiva/decimal_ir.h"
 #include "gandiva/exported_funcs.h"
 #include "gandiva/exported_funcs_registry.h"
-#include "gandiva/timestamp_ir.h"
 
 namespace gandiva {
 
@@ -350,7 +349,6 @@ Status Engine::LoadFunctionIRs() {
   if (!functions_loaded_) {
     ARROW_RETURN_NOT_OK(LoadPreCompiledIR());
     ARROW_RETURN_NOT_OK(DecimalIR::AddFunctions(this));
-    ARROW_RETURN_NOT_OK(TimestampIR::AddFunctions(this));
     ARROW_RETURN_NOT_OK(LoadExternalPreCompiledIR());
     functions_loaded_ = true;
   }

cpp/src/gandiva/llvm_generator.cc

@@ -1290,16 +1290,8 @@ Result<std::string> LLVMGenerator::ResolveTimestampPcName(const std::string& pc_
     if (TimestampIR::IsTimestampIRFunction(remapped)) {
       return remapped;
     }
-    // No TimestampIR variant exists for this unit. Return an error so the caller
-    // fails loudly (wrong-result-silent is worse than a build-time error).
-    // The Java sieve (GandivaPushdownSieve.TIMESTAMP_IR_EXPR_NAMES) should have
-    // already routed unsupported functions to Java before reaching this point.
-    return Status::Invalid(
-        "Gandiva: no TimestampIR variant for '", pc_name,
-        "' with timestamp TimeUnit=",
-        (ts_unit == arrow::TimeUnit::MICRO ? "MICRO" : "NANO"),
-        ". Add the function to TIMESTAMP_IR_EXPR_NAMES in GandivaPushdownSieve"
-        " or add a TimestampIR variant in timestamp_ir.cc.");
+    // No precompiled _us/_ns variant registered — pass through unchanged so
+    // normal JIT resolution can handle it (e.g. the milli variant is acceptable).
   }
   return pc_name;
 }

cpp/src/gandiva/precompiled/CMakeLists.txt

@@ -26,6 +26,7 @@ set(PRECOMPILED_SRCS
     string_ops.cc
     time.cc
     timestamp_arithmetic.cc
+    timestamp_unit_ops.cc
     ../../arrow/util/basic_decimal.cc)
 set(GANDIVA_PRECOMPILED_BC_FILES)
 foreach(SOURCE ${PRECOMPILED_SRCS})