[gcc/devel/omp/gcc-12] Fix bug in processing of array dimensions in data clauses.

[Kwok Yeung <kcy@gcc.gnu.org>]

https://gcc.gnu.org/g:49577050cb3e16a17e57c08c58bbe16f97bf94a5

commit 49577050cb3e16a17e57c08c58bbe16f97bf94a5
Author: Sandra Loosemore <sandra@codesourcery.com>
Date:   Tue Mar 31 14:29:09 2020 -0700

    Fix bug in processing of array dimensions in data clauses.
    
    The g++ front end wraps the array length and low_bound values in
    NON_LVALUE_EXPR, causing the subsequent tests for INTEGER_CST to fail.
    The test case c-c++-common/goacc/kernels-loop-annotation-1.c was
    tickling this bug and giving bogus errors in g++ because it was falling
    through to dynamic array code instead of recognizing the constant bounds.
    
    This patch was posted upstream here
    https://gcc.gnu.org/pipermail/gcc-patches/2020-March/542694.html
    but not yet committed.  It may be that some other fix for this problem
    is implemented on mainline instead; check before merging this patch.
    
    2020-03-31  Sandra Loosemore  <sandra@codesourcery.com>
    
            gcc/cp/
            * semantics.cc (handle_omp_array_sections_1): Call STRIP_NOPS
            on length and low_bound;
            (handle_omp_array_sections): Likewise.

Diff:
---
 gcc/cp/ChangeLog.omp | 6 ++++++
 gcc/cp/semantics.cc  | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/gcc/cp/ChangeLog.omp b/gcc/cp/ChangeLog.omp
index 74a672d653f..ead9de41a2c 100644
--- a/gcc/cp/ChangeLog.omp
+++ b/gcc/cp/ChangeLog.omp
@@ -1,3 +1,9 @@
+2020-03-31  Sandra Loosemore  <sandra@codesourcery.com>
+
+	* semantics.cc (handle_omp_array_sections_1): Call STRIP_NOPS
+	on length and low_bound;
+	(handle_omp_array_sections): Likewise.
+
 2020-03-27  Sandra Loosemore  <sandra@codesourcery.com>
 
 	* decl.cc (cp_unwrap_for_init): New.
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 7bcd8094bb1..2c0e1c7eaa0 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -5185,6 +5185,10 @@ handle_omp_array_sections_1 (tree c, tree t, vec<tree> &types,
   if (length)
     length = mark_rvalue_use (length);
   /* We need to reduce to real constant-values for checks below.  */
+  if (length)
+    STRIP_NOPS (length);
+  if (low_bound)
+    STRIP_NOPS (low_bound);
   if (length)
     length = fold_simple (length);
   if (low_bound)
@@ -5517,6 +5521,11 @@ handle_omp_array_sections (tree c, enum c_omp_region_type ort)
 	  tree low_bound = TREE_PURPOSE (t);
 	  tree length = TREE_VALUE (t);
 
+	  if (length)
+	    STRIP_NOPS (length);
+	  if (low_bound)
+	    STRIP_NOPS (low_bound);
+
 	  i--;
 	  if (low_bound
 	      && TREE_CODE (low_bound) == INTEGER_CST