https://github.com/robincaloudis created https://github.com/llvm/llvm-project/pull/86457
As reported in https://github.com/llvm/llvm-project/issues/82754, Metadirectives uses default for non-const user condition. This is unexpected as the OpenMP specification 5.1 allows dynamic `condition` selector within Metadirectives. In contrast static `condition` selector work. ### Example: ```c++ int non_const_val = 1; // A non const value makes the `condition` selector dynamic; a const value makes it static #pragma omp metadirective \ when( user= {condition(non_const_val > 0)} : parallel num_threads( num_threads ) ) \ default() { #pragma omp single assert( num_threads == omp_get_num_threads() ); } ``` where as `user` is called _selector set_ and `condition` is called _selector_ (must evaluate to true for the selector to be true). ## Background informations ### As of OpenMP 5.1, dynamic `condition` selectors seem to be allowed "[...] Any non-constant expression that is evaluated to determine the suitability of a variant is evaluated according to the data state trait in the dynamic trait set of the OpenMP context. The user selector set is dynamic if the _condition selector_ is present and the expression in the condition selector is not a constant expression; otherwise, it is static. [...]" ### Assembled grammar (copied from OpenMP 5.1. specification on [Metadirectives](https://www.openmp.org/spec-html/5.1/openmpsu28.html#x45-440002.3.4) and [Context Selectors](https://www.openmp.org/spec-html/5.1/openmpsu26.html#x43-420002.3.2)): There is a change that wrong semantics (meaning) are attached against the `trait-selector` when it is a dynamic condition selector ```c++ #pragma omp metadirective [clause[ [,] clause] ... ] new-line // where clause is one of the following: when(context-selector-specification: [directive-variant]) default([directive-variant]) // where context-selector-specification is context-selector-specification: trait-set-selector[,trait-set-selector[,...]] // where trait-set-selector is trait-set-selector: trait-set-selector-name={trait-selector[, trait-selector[, ...]]} ``` Specification of [Metadirectives](https://www.openmp.org/spec-html/5.1/openmpsu26.html#x43-420002.3.2) in OpenMP 5.1 Issue: https://github.com/llvm/llvm-project/issues/82754 >From bc962815d5587ffb16a178b4b766ffe36ee1c8a0 Mon Sep 17 00:00:00 2001 From: Robin Caloudis <robin.calou...@gmx.de> Date: Sun, 24 Mar 2024 21:37:33 +0100 Subject: [PATCH] Reproduce reported issue --- clang/test/OpenMP/metadirective_ast_print.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/clang/test/OpenMP/metadirective_ast_print.c b/clang/test/OpenMP/metadirective_ast_print.c index d9ff7e76452160..afc150610f197b 100644 --- a/clang/test/OpenMP/metadirective_ast_print.c +++ b/clang/test/OpenMP/metadirective_ast_print.c @@ -77,6 +77,11 @@ void foo(void) { : parallel) default(nothing) for (int i = 0; i < 16; i++) ; + + int non_const_val = 1; +#pragma omp metadirective when(user = {condition(non_const_val > 0)} \ + : parallel) default(nothing) + bar(); } // CHECK: void bar(void); @@ -107,5 +112,8 @@ void foo(void) { // CHECK-AMDGCN-NEXT: for (int i = 0; i < 100; i++) // CHECK: for (int i = 0; i < 16; i++) // CHECK: for (int i = 0; i < 16; i++) +// CHECK: int non_const_val = 1; +// CHECK-NEXT: #pragma omp parallel +// CHECK-NEXT: bar() #endif _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
