[flang-commits] [flang] [flang][OpenMP] Support `parallel loop` construct. (PR #127588)
Kareem Ergawy via flang-commits
flang-commits at lists.llvm.org
Fri Feb 21 06:46:08 PST 2025
https://github.com/ergawy updated https://github.com/llvm/llvm-project/pull/127588
>From ddf918141daf82d138272026056f14651560b6b4 Mon Sep 17 00:00:00 2001
From: ergawy <kareem.ergawy at amd.com>
Date: Tue, 18 Feb 2025 02:05:50 -0600
Subject: [PATCH] [flang][OpenMP] Support `parallel loop` construct.
Extends support for the `loop` directive by adding support for `parallel
loop` combined directive.
Parent PR: #127489. Only the latest commit is relevant.
---
.../OpenMP/GenericLoopConversion.cpp | 27 +++------------
flang/test/Lower/OpenMP/loop-directive.f90 | 33 +++++++++++++++++++
.../generic-loop-rewriting-todo.mlir | 16 ---------
.../Transforms/generic-loop-rewriting.mlir | 33 +++++++++++++++++++
4 files changed, 70 insertions(+), 39 deletions(-)
diff --git a/flang/lib/Optimizer/OpenMP/GenericLoopConversion.cpp b/flang/lib/Optimizer/OpenMP/GenericLoopConversion.cpp
index d3aece73b274f..bf94166edc079 100644
--- a/flang/lib/Optimizer/OpenMP/GenericLoopConversion.cpp
+++ b/flang/lib/Optimizer/OpenMP/GenericLoopConversion.cpp
@@ -52,8 +52,7 @@ class GenericLoopConversionPattern
rewriteStandaloneLoop(loopOp, rewriter);
break;
case GenericLoopCombinedInfo::ParallelLoop:
- llvm_unreachable(
- "not yet implemented: Combined `parallel loop` directive");
+ rewriteToWsloop(loopOp, rewriter);
break;
case GenericLoopCombinedInfo::TeamsLoop:
if (teamsLoopCanBeParallelFor(loopOp))
@@ -69,31 +68,12 @@ class GenericLoopConversionPattern
static mlir::LogicalResult
checkLoopConversionSupportStatus(mlir::omp::LoopOp loopOp) {
- GenericLoopCombinedInfo combinedInfo = findGenericLoopCombineInfo(loopOp);
-
- switch (combinedInfo) {
- case GenericLoopCombinedInfo::Standalone:
- break;
- case GenericLoopCombinedInfo::ParallelLoop:
- return loopOp.emitError(
- "not yet implemented: Combined `parallel loop` directive");
- case GenericLoopCombinedInfo::TeamsLoop:
- break;
- }
-
auto todo = [&loopOp](mlir::StringRef clauseName) {
return loopOp.emitError()
<< "not yet implemented: Unhandled clause " << clauseName << " in "
<< loopOp->getName() << " operation";
};
- // For `loop` and `teams loop` directives, `bind` is supported.
- // Additionally, for `teams loop`, semantic checking verifies that the
- // `bind` clause modifier is `teams`, so no need to check this here again.
- if (combinedInfo == GenericLoopCombinedInfo::ParallelLoop &&
- loopOp.getBindKind())
- return todo("bind");
-
if (loopOp.getOrder())
return todo("order");
@@ -147,8 +127,9 @@ class GenericLoopConversionPattern
mlir::omp::ClauseBindKind::Parallel)
return mlir::WalkResult::interrupt();
- // TODO check for combined `parallel loop` when we support
- // it.
+ if (combinedInfo == GenericLoopCombinedInfo::ParallelLoop)
+ return mlir::WalkResult::interrupt();
+
} else if (auto callOp =
mlir::dyn_cast<mlir::CallOpInterface>(nestedOp)) {
// Calls to non-OpenMP API runtime functions inhibits
diff --git a/flang/test/Lower/OpenMP/loop-directive.f90 b/flang/test/Lower/OpenMP/loop-directive.f90
index 13cf2bfd15135..ffa4a6ff24f24 100644
--- a/flang/test/Lower/OpenMP/loop-directive.f90
+++ b/flang/test/Lower/OpenMP/loop-directive.f90
@@ -261,3 +261,36 @@ subroutine teams_loop_can_be_parallel_for
tid = omp_get_thread_num()
END DO
end subroutine
+
+! CHECK-LABEL: func.func @_QPteams_loop_cannot_be_parallel_for_4
+subroutine teams_loop_cannot_be_parallel_for_4
+ implicit none
+ integer :: iter, iter2, tid, val(20)
+
+ ! CHECK: omp.teams {
+
+ ! Verify the outer `loop` directive was mapped to only `distribute`.
+ ! CHECK-NOT: omp.parallel {{.*}}
+ ! CHECK: omp.distribute {{.*}} {
+ ! CHECK-NEXT: omp.loop_nest {{.*}} {
+
+ ! Verify the inner `loop` directive was mapped to a worksharing loop.
+ ! CHECK: omp.wsloop {{.*}} {
+ ! CHECK: omp.loop_nest {{.*}} {
+ ! CHECK: }
+ ! CHECK: }
+
+ ! CHECK: }
+ ! CHECK: }
+
+ ! CHECK: }
+ !$omp target teams loop map(tofrom:val)
+ DO iter = 1, 5
+ !$omp parallel
+ !$omp loop
+ DO iter2 = 1, 5
+ val(iter+iter2) = iter+iter2
+ END DO
+ !$omp end parallel
+ END DO
+end subroutine
diff --git a/flang/test/Transforms/generic-loop-rewriting-todo.mlir b/flang/test/Transforms/generic-loop-rewriting-todo.mlir
index 25baffe34e394..e992296c9a837 100644
--- a/flang/test/Transforms/generic-loop-rewriting-todo.mlir
+++ b/flang/test/Transforms/generic-loop-rewriting-todo.mlir
@@ -1,21 +1,5 @@
// RUN: fir-opt --omp-generic-loop-conversion -verify-diagnostics %s
-func.func @_QPparallel_loop() {
- omp.parallel {
- %c0 = arith.constant 0 : i32
- %c10 = arith.constant 10 : i32
- %c1 = arith.constant 1 : i32
- // expected-error at below {{not yet implemented: Combined `parallel loop` directive}}
- omp.loop {
- omp.loop_nest (%arg3) : i32 = (%c0) to (%c10) inclusive step (%c1) {
- omp.yield
- }
- }
- omp.terminator
- }
- return
-}
-
omp.declare_reduction @add_reduction_i32 : i32 init {
^bb0(%arg0: i32):
%c0_i32 = arith.constant 0 : i32
diff --git a/flang/test/Transforms/generic-loop-rewriting.mlir b/flang/test/Transforms/generic-loop-rewriting.mlir
index 49caf242fe324..6996beeb9f430 100644
--- a/flang/test/Transforms/generic-loop-rewriting.mlir
+++ b/flang/test/Transforms/generic-loop-rewriting.mlir
@@ -45,3 +45,36 @@ func.func @_QPteams_loop() {
// CHECK: }
// CHECK: }
// CHECK: }
+
+func.func @_QPparallel_loop() {
+ %i = fir.alloca i32
+ omp.parallel {
+ %c0 = arith.constant 0 : i32
+ %c10 = arith.constant 10 : i32
+ %c1 = arith.constant 1 : i32
+ omp.loop private(@_QFteams_loopEi_private_i32 %i -> %arg2 : !fir.ref<i32>) {
+ omp.loop_nest (%arg3) : i32 = (%c0) to (%c10) inclusive step (%c1) {
+ fir.store %arg3 to %arg2 : !fir.ref<i32>
+ omp.yield
+ }
+ }
+ omp.terminator
+ }
+ return
+}
+
+// CHECK-LABEL: func.func @_QPparallel_loop
+// CHECK: %[[I:.*]] = fir.alloca i32
+// CHECK: omp.parallel {
+
+// CHECK: %[[LB:.*]] = arith.constant 0 : i32
+// CHECK: %[[UB:.*]] = arith.constant 10 : i32
+// CHECK: %[[STEP:.*]] = arith.constant 1 : i32
+// CHECK: omp.wsloop private(@{{.*}} %[[I]]
+// CHECK-SAME: -> %[[I_PRIV_ARG:[^[:space:]]+]] : !fir.ref<i32>) {
+// CHECK: omp.loop_nest (%{{.*}}) : i32 =
+// CHECK-SAME: (%[[LB]]) to (%[[UB]]) inclusive step (%[[STEP]]) {
+// CHECK: fir.store %{{.*}} to %[[I_PRIV_ARG]] : !fir.ref<i32>
+// CHECK: }
+// CHECK: }
+// CHECK: }
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