[gcc/devel/omp/gcc-12] OpenMP: Fix reverse offload GOMP_TARGET_REV IFN corner cases [PR107236]

[Tobias Burnus <burnus@gcc.gnu.org>]

https://gcc.gnu.org/g:497b44832fcef226515bb55271b87ecd12985a60

commit 497b44832fcef226515bb55271b87ecd12985a60
Author: Tobias Burnus <tobias@codesourcery.com>
Date:   Mon Oct 24 15:23:43 2022 +0200

    OpenMP: Fix reverse offload GOMP_TARGET_REV IFN corner cases [PR107236]
    
    For 'target parallel' and similarly nested directives, cgraph_node's
    calls_declare_variant_alt was not set in the parent region node but in
    cfun->decl. Hence, pass_omp_device_lower did not process handle the
    internal function GOMP_TARGET_REV. - Solution is to set it to the
    DECL_CONTEXT, which is set in adjust_context_and_scope.
    
    The cgraph_node::create_clone issue is exposed with -O2 for the existing
    libgomp.fortran/reverse-offload-1.f90.
    
            PR middle-end/107236
    
    gcc/ChangeLog:
            * omp-expand.cc (expand_omp_target): Set calls_declare_variant_alt
            in DECL_CONTEXT and not to cfun->decl.
            * cgraphclones.cc (cgraph_node::create_clone): Copy also the
            node's calls_declare_variant_alt value.
    
    gcc/testsuite/ChangeLog:
            * gfortran.dg/gomp/target-device-ancestor-6.f90: New test.
    
    (cherry picked from commit 178ac530fe67e4f2fc439cc4ce89bc19d571ca31)

Diff:
---
 gcc/ChangeLog.omp                                       | 11 +++++++++++
 gcc/cgraphclones.cc                                     |  1 +
 gcc/omp-expand.cc                                       | 13 ++++++-------
 gcc/testsuite/ChangeLog.omp                             |  8 ++++++++
 .../gfortran.dg/gomp/target-device-ancestor-6.f90       | 17 +++++++++++++++++
 5 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index e032c05148b..8fc8e06e9ff 100644
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,3 +1,14 @@
+2022-10-24  Tobias Burnus  <tobias@codesourcery.com>
+
+	Backported from master:
+	2022-10-24  Tobias Burnus  <tobias@codesourcery.com>
+
+	PR middle-end/107236
+	* omp-expand.cc (expand_omp_target): Set calls_declare_variant_alt
+	in DECL_CONTEXT and not to cfun->decl.
+	* cgraphclones.cc (cgraph_node::create_clone): Copy also the
+	node's calls_declare_variant_alt value.
+
 2022-10-21  Tobias Burnus  <tobias@codesourcery.com>
 
 	* omp-oacc-kernels-decompose.cc (top_level_omp_for_in_stmt,
diff --git a/gcc/cgraphclones.cc b/gcc/cgraphclones.cc
index eb0fa87b554..bb4b3c5407d 100644
--- a/gcc/cgraphclones.cc
+++ b/gcc/cgraphclones.cc
@@ -375,6 +375,7 @@ cgraph_node::create_clone (tree new_decl, profile_count prof_count,
   if (!new_inlined_to)
     prof_count = count.combine_with_ipa_count (prof_count);
   new_node->count = prof_count;
+  new_node->calls_declare_variant_alt = this->calls_declare_variant_alt;
 
   /* Update IPA profile.  Local profiles need no updating in original.  */
   if (update_original)
diff --git a/gcc/omp-expand.cc b/gcc/omp-expand.cc
index 6529f63362b..37c397089b4 100644
--- a/gcc/omp-expand.cc
+++ b/gcc/omp-expand.cc
@@ -10143,13 +10143,8 @@ expand_omp_target (struct omp_region *region)
 
       /* Handle the case that an inner ancestor:1 target is called by an outer
 	 target region. */
-      if (!is_ancestor)
-	cgraph_node::get (child_fn)->calls_declare_variant_alt
-	  |= cgraph_node::get (cfun->decl)->calls_declare_variant_alt;
-      else  /* Duplicate function to create empty nonhost variant. */
+      if (is_ancestor)
 	{
-	  /* Enable pass_omp_device_lower pass.  */
-	  cgraph_node::get (cfun->decl)->calls_declare_variant_alt = 1;
 	  cgraph_node *fn2_node;
 	  child_fn2 = build_decl (DECL_SOURCE_LOCATION (child_fn),
 				  FUNCTION_DECL,
@@ -10163,7 +10158,7 @@ expand_omp_target (struct omp_region *region)
 	  TREE_PUBLIC (child_fn2) = 0;
 	  DECL_UNINLINABLE (child_fn2) = 1;
 	  DECL_EXTERNAL (child_fn2) = 0;
-	  DECL_CONTEXT (child_fn2) = NULL_TREE;
+	  DECL_CONTEXT (child_fn2) = DECL_CONTEXT (child_fn);
 	  DECL_INITIAL (child_fn2) = make_node (BLOCK);
 	  BLOCK_SUPERCONTEXT (DECL_INITIAL (child_fn2)) = child_fn2;
 	  DECL_ATTRIBUTES (child_fn)
@@ -10187,6 +10182,10 @@ expand_omp_target (struct omp_region *region)
 	  fn2_node->force_output = 1;
 	  node->offloadable = 0;
 
+	  /* Enable pass_omp_device_lower pass.  */
+	  fn2_node = cgraph_node::get (DECL_CONTEXT (child_fn));
+	  fn2_node->calls_declare_variant_alt = 1;
+
 	  t = build_decl (DECL_SOURCE_LOCATION (child_fn),
 			  RESULT_DECL, NULL_TREE, void_type_node);
 	  DECL_ARTIFICIAL (t) = 1;
diff --git a/gcc/testsuite/ChangeLog.omp b/gcc/testsuite/ChangeLog.omp
index 0ded9edf750..5970a3baf7b 100644
--- a/gcc/testsuite/ChangeLog.omp
+++ b/gcc/testsuite/ChangeLog.omp
@@ -1,3 +1,11 @@
+2022-10-24  Tobias Burnus  <tobias@codesourcery.com>
+
+	Backported from master:
+	2022-10-24  Tobias Burnus  <tobias@codesourcery.com>
+
+	PR middle-end/107236
+	* gfortran.dg/gomp/target-device-ancestor-6.f90: New test.
+
 2022-10-21  Marcel Vollweiler  <marcel@codesourcery.com>
 
 	* c-c++-common/goacc/classify-kernels-unparallelized-graphite.c:
diff --git a/gcc/testsuite/gfortran.dg/gomp/target-device-ancestor-6.f90 b/gcc/testsuite/gfortran.dg/gomp/target-device-ancestor-6.f90
new file mode 100644
index 00000000000..821e7852e85
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/gomp/target-device-ancestor-6.f90
@@ -0,0 +1,17 @@
+! PR middle-end/107236
+
+! Did ICE before because IFN .GOMP_TARGET_REV was not
+! processed in omp-offload.cc.
+! Note: Test required ENABLE_OFFLOADING being true inside GCC.
+
+implicit none
+!$omp requires reverse_offload
+!$omp target parallel num_threads(4)
+  !$omp target device(ancestor:1)
+    call foo()
+  !$omp end target 
+!$omp end target parallel
+contains
+  subroutine foo
+  end
+end