[flang-commits] [flang] 7db4e6c - [OpenMP][LLVM] Update alloca IP after `PrivCB` in `OMPIRBUIlder` (#93920)

[via flang-commits]

Author: Kareem Ergawy
Date: 2024-06-05T05:13:47+02:00
New Revision: 7db4e6c1ec18785ad3f622556362d83c11d7efef

URL: https://github.com/llvm/llvm-project/commit/7db4e6c1ec18785ad3f622556362d83c11d7efef
DIFF: https://github.com/llvm/llvm-project/commit/7db4e6c1ec18785ad3f622556362d83c11d7efef.diff

LOG: [OpenMP][LLVM] Update alloca IP after `PrivCB` in `OMPIRBUIlder` (#93920)

Fixes a crash uncovered by
[pr77666.f90](https://github.com/llvm/llvm-test-suite/blob/main/Fortran/gfortran/regression/gomp/pr77666.f90)
in the test suite when delayed privatization is enabled by default.

In particular, whenever `PrivCB` (the callback responsible for
generating privatizaiton logic for an OMP variable) generates a
multi-block privatization region, the insertion point diverges: the BB
component of the IP can become a different BB from the parent block of
the instruction iterator component of the IP. This PR updates the IP to
make sure that the BB is the parent block of the instruction iterator.

Added: 
    flang/test/Lower/OpenMP/delayed-privatization-lower-allocatable-to-llvm.f90

Modified: 
    clang/test/OpenMP/parallel_codegen.cpp
    llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

Removed: 
    


################################################################################
diff  --git a/clang/test/OpenMP/parallel_codegen.cpp b/clang/test/OpenMP/parallel_codegen.cpp
index d545b4a9d9fa8..9082f1c3232af 100644
--- a/clang/test/OpenMP/parallel_codegen.cpp
+++ b/clang/test/OpenMP/parallel_codegen.cpp
@@ -822,8 +822,8 @@ int main (int argc, char **argv) {
 // CHECK3-NEXT:    [[TMP1:%.*]] = load i32, ptr [[TID_ADDR]], align 4
 // CHECK3-NEXT:    store i32 [[TMP1]], ptr [[TID_ADDR_LOCAL]], align 4
 // CHECK3-NEXT:    [[TID:%.*]] = load i32, ptr [[TID_ADDR_LOCAL]], align 4
-// CHECK3-NEXT:    [[TMP2:%.*]] = load i64, ptr [[LOADGEP__RELOADED]], align 8
 // CHECK3-NEXT:    [[VAR:%.*]] = alloca ptr, align 8
+// CHECK3-NEXT:    [[TMP2:%.*]] = load i64, ptr [[LOADGEP__RELOADED]], align 8
 // CHECK3-NEXT:    br label [[OMP_PAR_REGION:%.*]]
 // CHECK3:       omp.par.region:
 // CHECK3-NEXT:    [[TMP3:%.*]] = load ptr, ptr [[LOADGEP_ARGC_ADDR]], align 8
@@ -966,8 +966,8 @@ int main (int argc, char **argv) {
 // CHECK4-NEXT:    [[TMP1:%.*]] = load i32, ptr [[TID_ADDR]], align 4
 // CHECK4-NEXT:    store i32 [[TMP1]], ptr [[TID_ADDR_LOCAL]], align 4
 // CHECK4-NEXT:    [[TID:%.*]] = load i32, ptr [[TID_ADDR_LOCAL]], align 4
-// CHECK4-NEXT:    [[TMP2:%.*]] = load i64, ptr [[LOADGEP__RELOADED]], align 8
 // CHECK4-NEXT:    [[VAR:%.*]] = alloca ptr, align 8
+// CHECK4-NEXT:    [[TMP2:%.*]] = load i64, ptr [[LOADGEP__RELOADED]], align 8
 // CHECK4-NEXT:    br label [[OMP_PAR_REGION:%.*]]
 // CHECK4:       omp.par.region:
 // CHECK4-NEXT:    [[TMP3:%.*]] = load ptr, ptr [[LOADGEP_ARGC_ADDR]], align 8, !dbg [[DBG58:![0-9]+]]

diff  --git a/flang/test/Lower/OpenMP/delayed-privatization-lower-allocatable-to-llvm.f90 b/flang/test/Lower/OpenMP/delayed-privatization-lower-allocatable-to-llvm.f90
new file mode 100644
index 0000000000000..ac9a6d8746cf2
--- /dev/null
+++ b/flang/test/Lower/OpenMP/delayed-privatization-lower-allocatable-to-llvm.f90
@@ -0,0 +1,23 @@
+! Tests the OMPIRBuilder can handle multiple privatization regions that contain
+! multiple BBs (for example, for allocatables).
+
+! RUN: %flang -S -emit-llvm -fopenmp -mmlir --openmp-enable-delayed-privatization \
+! RUN:   -o - %s 2>&1 | FileCheck %s
+
+subroutine foo(x)
+  integer, allocatable :: x, y
+!$omp parallel private(x, y)
+  x = y
+!$omp end parallel
+end
+
+! CHECK-LABEL: define void @foo_
+! CHECK:         ret void
+! CHECK-NEXT:  }
+
+! CHECK-LABEL: define internal void @foo_..omp_par
+! CHECK-DAG:     call ptr @malloc
+! CHECK-DAG:     call ptr @malloc
+! CHECK-DAG:     call void @free
+! CHECK-DAG:     call void @free
+! CHECK:       }

diff  --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index cb4de9c8876dc..2c4b45255d059 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -1583,6 +1583,10 @@ IRBuilder<>::InsertPoint OpenMPIRBuilder::createParallel(
     } else {
       Builder.restoreIP(
           PrivCB(InnerAllocaIP, Builder.saveIP(), V, *Inner, ReplacementValue));
+      InnerAllocaIP = {
+          InnerAllocaIP.getBlock(),
+          InnerAllocaIP.getBlock()->getTerminator()->getIterator()};
+
       assert(ReplacementValue &&
              "Expected copy/create callback to set replacement value!");
       if (ReplacementValue == &V)