r350758 - [OpenMP] Add flag for preventing the extension to 64 bits for the collapse loop counter
Gheorghe-Teodor Bercea via cfe-commits
cfe-commits at lists.llvm.org
Wed Jan 9 12:38:35 PST 2019
Author: gbercea
Date: Wed Jan 9 12:38:35 2019
New Revision: 350758
URL: http://llvm.org/viewvc/llvm-project?rev=350758&view=rev
Log:
[OpenMP] Add flag for preventing the extension to 64 bits for the collapse loop counter
Summary: Introduce a compiler flag for cases when the user knows that the collapsed loop counter can be safely represented using at most 32 bits. This will prevent the emission of expensive mathematical operations (such as the div operation) on the iteration variable using 64 bits where 32 bit operations are sufficient.
Reviewers: ABataev, caomhin
Reviewed By: ABataev
Subscribers: hfinkel, kkwli0, guansong, cfe-commits
Differential Revision: https://reviews.llvm.org/D55928
Modified:
cfe/trunk/docs/OpenMPSupport.rst
cfe/trunk/include/clang/Basic/LangOptions.def
cfe/trunk/include/clang/Driver/Options.td
cfe/trunk/lib/Driver/ToolChains/Clang.cpp
cfe/trunk/lib/Frontend/CompilerInvocation.cpp
cfe/trunk/lib/Sema/SemaOpenMP.cpp
cfe/trunk/test/OpenMP/nvptx_target_teams_distribute_parallel_for_codegen.cpp
Modified: cfe/trunk/docs/OpenMPSupport.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/OpenMPSupport.rst?rev=350758&r1=350757&r2=350758&view=diff
==============================================================================
--- cfe/trunk/docs/OpenMPSupport.rst (original)
+++ cfe/trunk/docs/OpenMPSupport.rst Wed Jan 9 12:38:35 2019
@@ -108,6 +108,16 @@ are stored in the global memory. In `Cud
between the threads and it is user responsibility to share the required data
between the threads in the parallel regions.
+Collapsed loop nest counter
+---------------------------
+
+When using the collapse clause on a loop nest the default behaviour is to
+automatically extend the representation of the loop counter to 64 bits for
+the cases where the sizes of the collapsed loops are not known at compile
+time. To prevent this conservative choice and use at most 32 bits,
+compile your program with the `-fopenmp-optimistic-collapse`.
+
+
Features not supported or with limited support for Cuda devices
---------------------------------------------------------------
Modified: cfe/trunk/include/clang/Basic/LangOptions.def
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/LangOptions.def?rev=350758&r1=350757&r2=350758&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/LangOptions.def (original)
+++ cfe/trunk/include/clang/Basic/LangOptions.def Wed Jan 9 12:38:35 2019
@@ -207,6 +207,7 @@ LANGOPT(OpenMPCUDAForceFullRuntime , 1,
LANGOPT(OpenMPHostCXXExceptions , 1, 0, "C++ exceptions handling in the host code.")
LANGOPT(OpenMPCUDANumSMs , 32, 0, "Number of SMs for CUDA devices.")
LANGOPT(OpenMPCUDABlocksPerSM , 32, 0, "Number of blocks per SM for CUDA devices.")
+LANGOPT(OpenMPOptimisticCollapse , 1, 0, "Use at most 32 bits to represent the collapsed loop nest counter.")
LANGOPT(RenderScript , 1, 0, "RenderScript")
LANGOPT(CUDAIsDevice , 1, 0, "compiling for CUDA device")
Modified: cfe/trunk/include/clang/Driver/Options.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=350758&r1=350757&r2=350758&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/Options.td (original)
+++ cfe/trunk/include/clang/Driver/Options.td Wed Jan 9 12:38:35 2019
@@ -1574,6 +1574,10 @@ def fopenmp_cuda_number_of_sm_EQ : Joine
Flags<[CC1Option, NoArgumentUnused, HelpHidden]>;
def fopenmp_cuda_blocks_per_sm_EQ : Joined<["-"], "fopenmp-cuda-blocks-per-sm=">, Group<f_Group>,
Flags<[CC1Option, NoArgumentUnused, HelpHidden]>;
+def fopenmp_optimistic_collapse : Flag<["-"], "fopenmp-optimistic-collapse">, Group<f_Group>,
+ Flags<[CC1Option, NoArgumentUnused, HelpHidden]>;
+def fno_openmp_optimistic_collapse : Flag<["-"], "fno-openmp-optimistic-collapse">, Group<f_Group>,
+ Flags<[NoArgumentUnused, HelpHidden]>;
def fno_optimize_sibling_calls : Flag<["-"], "fno-optimize-sibling-calls">, Group<f_Group>;
def foptimize_sibling_calls : Flag<["-"], "foptimize-sibling-calls">, Group<f_Group>;
def fno_escaping_block_tail_calls : Flag<["-"], "fno-escaping-block-tail-calls">, Group<f_Group>, Flags<[CC1Option]>;
Modified: cfe/trunk/lib/Driver/ToolChains/Clang.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains/Clang.cpp?rev=350758&r1=350757&r2=350758&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/ToolChains/Clang.cpp (original)
+++ cfe/trunk/lib/Driver/ToolChains/Clang.cpp Wed Jan 9 12:38:35 2019
@@ -4434,6 +4434,10 @@ void Clang::ConstructJob(Compilation &C,
Args.AddAllArgs(CmdArgs, options::OPT_fopenmp_version_EQ);
Args.AddAllArgs(CmdArgs, options::OPT_fopenmp_cuda_number_of_sm_EQ);
Args.AddAllArgs(CmdArgs, options::OPT_fopenmp_cuda_blocks_per_sm_EQ);
+ if (Args.hasFlag(options::OPT_fopenmp_optimistic_collapse,
+ options::OPT_fno_openmp_optimistic_collapse,
+ /*Default=*/false))
+ CmdArgs.push_back("-fopenmp-optimistic-collapse");
// When in OpenMP offloading mode with NVPTX target, forward
// cuda-mode flag
Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=350758&r1=350757&r2=350758&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original)
+++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Wed Jan 9 12:38:35 2019
@@ -2846,6 +2846,11 @@ static void ParseLangArgs(LangOptions &O
Opts.OpenMPCUDABlocksPerSM, Diags);
}
+ // Prevent auto-widening the representation of loop counters during an
+ // OpenMP collapse clause.
+ Opts.OpenMPOptimisticCollapse =
+ Args.hasArg(options::OPT_fopenmp_optimistic_collapse) ? 1 : 0;
+
// Get the OpenMP target triples if any.
if (Arg *A = Args.getLastArg(options::OPT_fopenmp_targets_EQ)) {
Modified: cfe/trunk/lib/Sema/SemaOpenMP.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOpenMP.cpp?rev=350758&r1=350757&r2=350758&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaOpenMP.cpp (original)
+++ cfe/trunk/lib/Sema/SemaOpenMP.cpp Wed Jan 9 12:38:35 2019
@@ -4136,7 +4136,7 @@ bool OpenMPIterationSpaceChecker::setSte
if (!TestIsLessOp.hasValue())
TestIsLessOp = IsConstPos || (IsUnsigned && !Subtract);
if (UB && (IsConstZero ||
- (TestIsLessOp.getValue() ?
+ (TestIsLessOp.getValue() ?
(IsConstNeg || (IsUnsigned && Subtract)) :
(IsConstPos || (IsUnsigned && !Subtract))))) {
SemaRef.Diag(NewStep->getExprLoc(),
@@ -4311,7 +4311,7 @@ bool OpenMPIterationSpaceChecker::checkA
Op == OO_Less || Op == OO_Greater, CE->getSourceRange(),
CE->getOperatorLoc());
break;
- case OO_ExclaimEqual:
+ case OO_ExclaimEqual:
return setUB(getInitLCDecl(CE->getArg(0)) == LCDecl ?
CE->getArg(1) : CE->getArg(0),
/*LessOp=*/llvm::None,
@@ -4569,7 +4569,7 @@ Expr *OpenMPIterationSpaceChecker::build
ExprResult CondExpr =
SemaRef.BuildBinOp(S, DefaultLoc,
- TestIsLessOp.getValue() ?
+ TestIsLessOp.getValue() ?
(TestIsStrictOp ? BO_LT : BO_LE) :
(TestIsStrictOp ? BO_GT : BO_GE),
NewLB.get(), NewUB.get());
@@ -5270,13 +5270,14 @@ checkOpenMPLoop(OpenMPDirectiveKind DKin
// Choose either the 32-bit or 64-bit version.
ExprResult LastIteration = LastIteration64;
- if (LastIteration32.isUsable() &&
- C.getTypeSize(LastIteration32.get()->getType()) == 32 &&
- (AllCountsNeedLessThan32Bits || NestedLoopCount == 1 ||
- fitsInto(
- /*Bits=*/32,
- LastIteration32.get()->getType()->hasSignedIntegerRepresentation(),
- LastIteration64.get(), SemaRef)))
+ if (SemaRef.getLangOpts().OpenMPOptimisticCollapse ||
+ (LastIteration32.isUsable() &&
+ C.getTypeSize(LastIteration32.get()->getType()) == 32 &&
+ (AllCountsNeedLessThan32Bits || NestedLoopCount == 1 ||
+ fitsInto(
+ /*Bits=*/32,
+ LastIteration32.get()->getType()->hasSignedIntegerRepresentation(),
+ LastIteration64.get(), SemaRef))))
LastIteration = LastIteration32;
QualType VType = LastIteration.get()->getType();
QualType RealVType = VType;
@@ -13116,7 +13117,7 @@ Sema::ActOnOpenMPMapClause(ArrayRef<Open
continue;
}
assert(Count < OMPMapClause::NumberOfModifiers &&
- "Modifiers exceed the allowed number of map type modifiers");
+ "Modifiers exceed the allowed number of map type modifiers");
Modifiers[Count] = MapTypeModifiers[I];
ModifiersLoc[Count] = MapTypeModifiersLoc[I];
++Count;
Modified: cfe/trunk/test/OpenMP/nvptx_target_teams_distribute_parallel_for_codegen.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/OpenMP/nvptx_target_teams_distribute_parallel_for_codegen.cpp?rev=350758&r1=350757&r2=350758&view=diff
==============================================================================
--- cfe/trunk/test/OpenMP/nvptx_target_teams_distribute_parallel_for_codegen.cpp (original)
+++ cfe/trunk/test/OpenMP/nvptx_target_teams_distribute_parallel_for_codegen.cpp Wed Jan 9 12:38:35 2019
@@ -1,6 +1,7 @@
// Test target codegen - host bc file has to be created first.
// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=45 -fopenmp-cuda-mode -x c++ -triple powerpc64le-unknown-unknown -fopenmp-targets=nvptx64-nvidia-cuda -emit-llvm-bc %s -o %t-ppc-host.bc
-// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=45 -fopenmp-cuda-mode -x c++ -triple nvptx64-unknown-unknown -fopenmp-targets=nvptx64-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-ppc-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-64
+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=45 -fopenmp-cuda-mode -x c++ -triple nvptx64-unknown-unknown -fopenmp-targets=nvptx64-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-ppc-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-64 --check-prefix CHECK-DIV64
+// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=45 -fopenmp-cuda-mode -x c++ -triple nvptx64-unknown-unknown -fopenmp-targets=nvptx64-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-ppc-host.bc -fopenmp-optimistic-collapse -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-DIV32
// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=45 -fopenmp-cuda-mode -x c++ -triple i386-unknown-unknown -fopenmp-targets=nvptx-nvidia-cuda -emit-llvm-bc %s -o %t-x86-host.bc
// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=45 -fopenmp-cuda-mode -x c++ -triple nvptx-unknown-unknown -fopenmp-targets=nvptx-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-x86-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-32
// RUN: %clang_cc1 -verify -fopenmp -fopenmp-version=45 -fopenmp-cuda-mode -fexceptions -fcxx-exceptions -x c++ -triple nvptx-unknown-unknown -fopenmp-targets=nvptx-nvidia-cuda -emit-llvm %s -fopenmp-is-device -fopenmp-host-ir-file-path %t-x86-host.bc -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-32
@@ -9,11 +10,12 @@
#define HEADER
// Check that the execution mode of all 5 target regions on the gpu is set to SPMD Mode.
-// CHECK-DAG: {{@__omp_offloading_.+l32}}_exec_mode = weak constant i8 0
-// CHECK-DAG: {{@__omp_offloading_.+l38}}_exec_mode = weak constant i8 0
-// CHECK-DAG: {{@__omp_offloading_.+l43}}_exec_mode = weak constant i8 0
-// CHECK-DAG: {{@__omp_offloading_.+l48}}_exec_mode = weak constant i8 0
-// CHECK-DAG: {{@__omp_offloading_.+l56}}_exec_mode = weak constant i8 0
+// CHECK-DAG: {{@__omp_offloading_.+l34}}_exec_mode = weak constant i8 0
+// CHECK-DAG: {{@__omp_offloading_.+l40}}_exec_mode = weak constant i8 0
+// CHECK-DAG: {{@__omp_offloading_.+l45}}_exec_mode = weak constant i8 0
+// CHECK-DAG: {{@__omp_offloading_.+l50}}_exec_mode = weak constant i8 0
+// CHECK-DAG: {{@__omp_offloading_.+l58}}_exec_mode = weak constant i8 0
+// CHECK-DAG: {{@__omp_offloading_.+l65}}_exec_mode = weak constant i8 0
#define N 1000
#define M 10
@@ -80,7 +82,7 @@ int bar(int n){
// CHECK-DAG: [[KERNEL_SIZE:@.+]] = internal unnamed_addr constant i{{64|32}} 4
// CHECK-DAG: [[KERNEL_SHARED:@.+]] = internal unnamed_addr constant i16 1
-// CHECK-LABEL: define {{.*}}void {{@__omp_offloading_.+}}_l32(
+// CHECK-LABEL: define {{.*}}void {{@__omp_offloading_.+}}_l34(
// CHECK-DAG: [[THREAD_LIMIT:%.+]] = call i32 @llvm.nvvm.read.ptx.sreg.ntid.x()
// CHECK: call void @__kmpc_spmd_kernel_init(i32 [[THREAD_LIMIT]], i16 0, i16 0)
// CHECK: call void @__kmpc_get_team_static_memory(i16 1, i8* addrspacecast (i8 addrspace(3)* getelementptr inbounds ([[MEM_TY]], [[MEM_TY]] addrspace(3)* [[SHARED_GLOBAL_RD]], i32 0, i32 0, i32 0) to i8*), i{{64|32}} 4, i16 1, i8** addrspacecast (i8* addrspace(3)* [[KERNEL_PTR]] to i8**))
@@ -214,16 +216,19 @@ int bar(int n){
// CHECK: call void @__kmpc_spmd_kernel_deinit_v2(i16 0)
// CHECK: ret void
-// CHECK: define internal void [[OUTL4]](
+// CHECK-32: define internal void [[OUTL4]](
+// CHECK-64: define internal void [[OUTL4]](
// CHECK: call void @__kmpc_for_static_init_4({{.+}}, {{.+}}, {{.+}} 33,
// CHECK: call void @__kmpc_for_static_fini(
// CHECK: ret void
-// CHECK: define weak void @__omp_offloading_{{.*}}_l56(i[[SZ:64|32]] %{{[^,]+}}, [10 x [10 x i32]]* dereferenceable{{.*}})
+// CHECK: define weak void @__omp_offloading_{{.*}}_l58(i[[SZ:64|32]] %{{[^,]+}}, [10 x [10 x i32]]* dereferenceable{{.*}})
// CHECK: call void [[OUTLINED:@__omp_outlined.*]](i32* %{{.+}}, i32* %{{.+}}, i[[SZ]] %{{.*}}, i[[SZ]] %{{.*}}, i[[SZ]] %{{.*}}, [10 x [10 x i32]]* %{{.*}})
// CHECK: define internal void [[OUTLINED]](i32* noalias %{{.*}}, i32* noalias %{{.*}} i[[SZ]] %{{.+}}, i[[SZ]] %{{.+}}, i[[SZ]] %{{.+}}, [10 x [10 x i32]]* dereferenceable{{.*}})
+// CHECK-DIV64: div i64
+// CHECK-DIV32-NO: div i64
-// CHECK: define weak void @__omp_offloading_{{.*}}_l63(i[[SZ:64|32]] %{{[^,]+}}, [1000 x i32]* dereferenceable{{.*}}, i32* %{{[^)]+}})
+// CHECK: define weak void @__omp_offloading_{{.*}}_l65(i[[SZ:64|32]] %{{[^,]+}}, [1000 x i32]* dereferenceable{{.*}}, i32* %{{[^)]+}})
// CHECK: call void [[OUTLINED:@__omp_outlined.*]](i32* %{{.+}}, i32* %{{.+}}, i[[SZ]] %{{.*}}, i[[SZ]] %{{.*}}, i[[SZ]] %{{.*}}, [1000 x i32]* %{{.*}}, i32* %{{.*}})
// CHECK: define internal void [[OUTLINED]](i32* noalias %{{.*}}, i32* noalias %{{.*}} i[[SZ]] %{{.+}}, i[[SZ]] %{{.+}}, i[[SZ]] %{{.+}}, [1000 x i32]* dereferenceable{{.*}}, i32* %{{.*}})
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