[llvm] c771eaf - [OpenMP] Ensure to not use SPMD mode in the absence of parallel regions

[Johannes Doerfert via llvm-commits]

Author: Johannes Doerfert
Date: 2022-07-07T16:49:22-05:00
New Revision: c771eaf07ef8d82d65497e6e9f8be88f7d976301

URL: https://github.com/llvm/llvm-project/commit/c771eaf07ef8d82d65497e6e9f8be88f7d976301
DIFF: https://github.com/llvm/llvm-project/commit/c771eaf07ef8d82d65497e6e9f8be88f7d976301.diff

LOG: [OpenMP] Ensure to not use SPMD mode in the absence of parallel regions

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/OpenMPOpt.cpp
    llvm/test/Transforms/OpenMP/get_hardware_num_threads_in_block_fold.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
index 227ad8501f25a..a3bdc2325f506 100644
--- a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
+++ b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
@@ -3340,6 +3340,9 @@ struct AAKernelInfoFunction : AAKernelInfo {
   }
 
   bool changeToSPMDMode(Attributor &A, ChangeStatus &Changed) {
+    if (!mayContainParallelRegion())
+      return false;
+
     auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
 
     if (!SPMDCompatibilityTracker.isAssumed()) {

diff  --git a/llvm/test/Transforms/OpenMP/get_hardware_num_threads_in_block_fold.ll b/llvm/test/Transforms/OpenMP/get_hardware_num_threads_in_block_fold.ll
index 57eaebc7e141c..982605e05eb3a 100644
--- a/llvm/test/Transforms/OpenMP/get_hardware_num_threads_in_block_fold.ll
+++ b/llvm/test/Transforms/OpenMP/get_hardware_num_threads_in_block_fold.ll
@@ -8,9 +8,9 @@ target triple = "nvptx64"
 
 @G = external global i32
 ;.
-; CHECK: @[[KERNEL0_EXEC_MODE:[a-zA-Z0-9_$"\\.-]+]] = weak constant i8 3
+; CHECK: @[[KERNEL0_EXEC_MODE:[a-zA-Z0-9_$"\\.-]+]] = weak constant i8 1
 ; CHECK: @[[G:[a-zA-Z0-9_$"\\.-]+]] = external global i32
-; CHECK: @[[KERNEL1_EXEC_MODE:[a-zA-Z0-9_$"\\.-]+]] = weak constant i8 3
+; CHECK: @[[KERNEL1_EXEC_MODE:[a-zA-Z0-9_$"\\.-]+]] = weak constant i8 1
 ; CHECK: @[[KERNEL2_EXEC_MODE:[a-zA-Z0-9_$"\\.-]+]] = weak constant i8 3
 ; CHECK: @[[GLOB0:[0-9]+]] = private unnamed_addr constant [23 x i8] c"
 ; CHECK: @[[GLOB1:[0-9]+]] = private unnamed_addr constant [[STRUCT_IDENT_T:%.*]] { i32 0, i32 2, i32 0, i32 22, i8* getelementptr inbounds ([23 x i8], [23 x i8]* @[[GLOB0]], i32 0, i32 0) }, align 8
@@ -18,11 +18,11 @@ target triple = "nvptx64"
 define weak void @kernel0() #0 {
 ; CHECK-LABEL: define {{[^@]+}}@kernel0
 ; CHECK-SAME: () #[[ATTR0:[0-9]+]] {
-; CHECK-NEXT:    [[I:%.*]] = call i32 @__kmpc_target_init(%struct.ident_t* null, i8 2, i1 false, i1 false)
+; CHECK-NEXT:    [[I:%.*]] = call i32 @__kmpc_target_init(%struct.ident_t* null, i8 1, i1 false, i1 false)
 ; CHECK-NEXT:    call void @helper0() #[[ATTR1:[0-9]+]]
 ; CHECK-NEXT:    call void @helper1() #[[ATTR1]]
 ; CHECK-NEXT:    call void @helper2() #[[ATTR1]]
-; CHECK-NEXT:    call void @__kmpc_target_deinit(%struct.ident_t* null, i8 2, i1 false)
+; CHECK-NEXT:    call void @__kmpc_target_deinit(%struct.ident_t* null, i8 1, i1 false)
 ; CHECK-NEXT:    ret void
 ;
   %i = call i32 @__kmpc_target_init(%struct.ident_t* null, i8 1, i1 false, i1 false)
@@ -38,9 +38,9 @@ define weak void @kernel0() #0 {
 define weak void @kernel1() #0 {
 ; CHECK-LABEL: define {{[^@]+}}@kernel1
 ; CHECK-SAME: () #[[ATTR0]] {
-; CHECK-NEXT:    [[I:%.*]] = call i32 @__kmpc_target_init(%struct.ident_t* null, i8 2, i1 false, i1 false)
+; CHECK-NEXT:    [[I:%.*]] = call i32 @__kmpc_target_init(%struct.ident_t* null, i8 1, i1 false, i1 false)
 ; CHECK-NEXT:    call void @helper1() #[[ATTR1]]
-; CHECK-NEXT:    call void @__kmpc_target_deinit(%struct.ident_t* null, i8 2, i1 false)
+; CHECK-NEXT:    call void @__kmpc_target_deinit(%struct.ident_t* null, i8 1, i1 false)
 ; CHECK-NEXT:    ret void
 ;
   %i = call i32 @__kmpc_target_init(%struct.ident_t* null, i8 1, i1 false, i1 false)