Expose "noduplicate" attribute as a property for intrinsics.

The "noduplicate" function attribute exists to prevent certain optimizations
from duplicating calls to the function. This is important on platforms where
certain function call duplications are unsafe (for example execution barriers
for CUDA and OpenCL).

This patch makes it possible to specify intrinsics as "noduplicate" and
translates that to the appropriate function attribute.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204200 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/IR/Intrinsics.td b/include/llvm/IR/Intrinsics.td
index 755c9c2b1fea8bdc2febcdbf01a6cf38f9261acd..94c7b50ac8e30ce828a8e9fe30b0c67825ff3192 100644 (file)
--- a/include/llvm/IR/Intrinsics.td
+++ b/include/llvm/IR/Intrinsics.td
@@ -69,6 +69,10 @@ class ReadNone<int argNo> : IntrinsicProperty {
 
 def IntrNoReturn : IntrinsicProperty;
 
+// IntrNoduplicate - Calls to this intrinsic cannot be duplicated.
+// Parallels the noduplicate attribute on LLVM IR functions.
+def IntrNoDuplicate : IntrinsicProperty;
+
 //===----------------------------------------------------------------------===//
 // Types used by intrinsics.
 //===----------------------------------------------------------------------===//

diff --git a/include/llvm/IR/IntrinsicsNVVM.td b/include/llvm/IR/IntrinsicsNVVM.td
index a372c22e43477dda0a9d5b0d13d10a107d2f91aa..7f72ce8b66fb5a9673509509c33aef3e1ba7283a 100644 (file)
--- a/include/llvm/IR/IntrinsicsNVVM.td
+++ b/include/llvm/IR/IntrinsicsNVVM.td
@@ -730,15 +730,15 @@ def llvm_anyi64ptr_ty     : LLVMAnyPointerType<llvm_i64_ty>;     // (space)i64*
 
 // Bar.Sync
   def int_cuda_syncthreads : GCCBuiltin<"__syncthreads">,
-      Intrinsic<[], [], []>;
+      Intrinsic<[], [], [IntrNoDuplicate]>;
   def int_nvvm_barrier0 : GCCBuiltin<"__nvvm_bar0">,
-      Intrinsic<[], [], []>;
+      Intrinsic<[], [], [IntrNoDuplicate]>;
   def int_nvvm_barrier0_popc : GCCBuiltin<"__nvvm_bar0_popc">,
-      Intrinsic<[llvm_i32_ty], [llvm_i32_ty], []>;
+      Intrinsic<[llvm_i32_ty], [llvm_i32_ty], [IntrNoDuplicate]>;
   def int_nvvm_barrier0_and : GCCBuiltin<"__nvvm_bar0_and">,
-      Intrinsic<[llvm_i32_ty], [llvm_i32_ty], []>;
+      Intrinsic<[llvm_i32_ty], [llvm_i32_ty], [IntrNoDuplicate]>;
   def int_nvvm_barrier0_or : GCCBuiltin<"__nvvm_bar0_or">,
-      Intrinsic<[llvm_i32_ty], [llvm_i32_ty], []>;
+      Intrinsic<[llvm_i32_ty], [llvm_i32_ty], [IntrNoDuplicate]>;
 
   // Membar
   def int_nvvm_membar_cta : GCCBuiltin<"__nvvm_membar_cta">,

diff --git a/test/CodeGen/NVPTX/noduplicate-syncthreads.ll b/test/CodeGen/NVPTX/noduplicate-syncthreads.ll
new file mode 100644 (file)
index 0000000..64745fc
--- /dev/null
+++ b/test/CodeGen/NVPTX/noduplicate-syncthreads.ll
@@ -0,0 +1,74 @@
+; RUN: opt < %s -O3 -S | FileCheck %s
+
+; Make sure the call to syncthreads is not duplicate here by the LLVM
+; optimizations, because it has the noduplicate attribute set.
+
+; CHECK: call void @llvm.cuda.syncthreads
+; CHECK-NOT: call void @llvm.cuda.syncthreads
+
+; Function Attrs: nounwind
+define void @foo(float* %output) #1 {
+entry:
+  %output.addr = alloca float*, align 8
+  store float* %output, float** %output.addr, align 8
+  %0 = load float** %output.addr, align 8
+  %arrayidx = getelementptr inbounds float* %0, i64 0
+  %1 = load float* %arrayidx, align 4
+  %conv = fpext float %1 to double
+  %cmp = fcmp olt double %conv, 1.000000e+01
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:                                          ; preds = %entry
+  %2 = load float** %output.addr, align 8
+  %3 = load float* %2, align 4
+  %conv1 = fpext float %3 to double
+  %add = fadd double %conv1, 1.000000e+00
+  %conv2 = fptrunc double %add to float
+  store float %conv2, float* %2, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %4 = load float** %output.addr, align 8
+  %5 = load float* %4, align 4
+  %conv3 = fpext float %5 to double
+  %add4 = fadd double %conv3, 2.000000e+00
+  %conv5 = fptrunc double %add4 to float
+  store float %conv5, float* %4, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  call void @llvm.cuda.syncthreads()
+  %6 = load float** %output.addr, align 8
+  %arrayidx6 = getelementptr inbounds float* %6, i64 0
+  %7 = load float* %arrayidx6, align 4
+  %conv7 = fpext float %7 to double
+  %cmp8 = fcmp olt double %conv7, 1.000000e+01
+  br i1 %cmp8, label %if.then9, label %if.else13
+
+if.then9:                                         ; preds = %if.end
+  %8 = load float** %output.addr, align 8
+  %9 = load float* %8, align 4
+  %conv10 = fpext float %9 to double
+  %add11 = fadd double %conv10, 3.000000e+00
+  %conv12 = fptrunc double %add11 to float
+  store float %conv12, float* %8, align 4
+  br label %if.end17
+
+if.else13:                                        ; preds = %if.end
+  %10 = load float** %output.addr, align 8
+  %11 = load float* %10, align 4
+  %conv14 = fpext float %11 to double
+  %add15 = fadd double %conv14, 4.000000e+00
+  %conv16 = fptrunc double %add15 to float
+  store float %conv16, float* %10, align 4
+  br label %if.end17
+
+if.end17:                                         ; preds = %if.else13, %if.then9
+  ret void
+}
+
+; Function Attrs: noduplicate nounwind
+declare void @llvm.cuda.syncthreads() #2
+
+!0 = metadata !{void (float*)* @foo, metadata !"kernel", i32 1}
+!1 = metadata !{null, metadata !"align", i32 8}

diff --git a/test/Feature/intrinsic-noduplicate.ll b/test/Feature/intrinsic-noduplicate.ll
new file mode 100644 (file)
index 0000000..9a2b0ab
--- /dev/null
+++ b/test/Feature/intrinsic-noduplicate.ll
@@ -0,0 +1,9 @@
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+; Make sure LLVM knows about the noduplicate attribute on the
+; llvm.cuda.syncthreads intrinsic.
+
+declare void @llvm.cuda.syncthreads()
+
+; CHECK: declare void @llvm.cuda.syncthreads() #[[ATTRNUM:[0-9]+]]
+; CHECK: attributes #[[ATTRNUM]] = { noduplicate nounwind }

diff --git a/utils/TableGen/CodeGenIntrinsics.h b/utils/TableGen/CodeGenIntrinsics.h
index edbb18bbcf50141250ed619abed744a2f23896d8..06daa97b66e019e5ff1a93b4e2bbde14be5ab59d 100644 (file)
--- a/utils/TableGen/CodeGenIntrinsics.h
+++ b/utils/TableGen/CodeGenIntrinsics.h
@@ -73,6 +73,9 @@ namespace llvm {
     /// canThrow - True if the intrinsic can throw.
     bool canThrow;
 
+    /// isNoDuplicate - True if the intrinsic is marked as noduplicate.
+    bool isNoDuplicate;
+
     /// isNoReturn - True if the intrinsic is no-return.
     bool isNoReturn;
 

diff --git a/utils/TableGen/CodeGenTarget.cpp b/utils/TableGen/CodeGenTarget.cpp
index 1f47675eb5e7a7d3e1a6a65f7165ae7aed6c6f42..884af4c7cb7ca97e24d92704977ddb5d8d5c7bdd 100644 (file)
--- a/utils/TableGen/CodeGenTarget.cpp
+++ b/utils/TableGen/CodeGenTarget.cpp
@@ -446,6 +446,7 @@ CodeGenIntrinsic::CodeGenIntrinsic(Record *R) {
   isCommutative = false;
   canThrow = false;
   isNoReturn = false;
+  isNoDuplicate = false;
 
   if (DefName.size() <= 4 ||
       std::string(DefName.begin(), DefName.begin() + 4) != "int_")
@@ -570,6 +571,8 @@ CodeGenIntrinsic::CodeGenIntrinsic(Record *R) {
       isCommutative = true;
     else if (Property->getName() == "Throws")
       canThrow = true;
+    else if (Property->getName() == "IntrNoDuplicate")
+      isNoDuplicate = true;
     else if (Property->getName() == "IntrNoReturn")
       isNoReturn = true;
     else if (Property->isSubClassOf("NoCapture")) {

diff --git a/utils/TableGen/IntrinsicEmitter.cpp b/utils/TableGen/IntrinsicEmitter.cpp
index cf6934cb169e233ad80a2358c334835077ef8932..1b281288a4ed579c21d09ff6a6b36837b6e34e8c 100644 (file)
--- a/utils/TableGen/IntrinsicEmitter.cpp
+++ b/utils/TableGen/IntrinsicEmitter.cpp
@@ -502,6 +502,9 @@ struct AttributeComparator {
     if (L->canThrow != R->canThrow)
       return R->canThrow;
 
+    if (L->isNoDuplicate != R->isNoDuplicate)
+      return R->isNoDuplicate;
+
     if (L->isNoReturn != R->isNoReturn)
       return R->isNoReturn;
 
@@ -616,7 +619,8 @@ EmitAttributes(const std::vector<CodeGenIntrinsic> &Ints, raw_ostream &OS) {
 
     ModRefKind modRef = getModRefKind(intrinsic);
 
-    if (!intrinsic.canThrow || modRef || intrinsic.isNoReturn) {
+    if (!intrinsic.canThrow || modRef || intrinsic.isNoReturn ||
+        intrinsic.isNoDuplicate) {
       OS << "      const Attribute::AttrKind Atts[] = {";
       bool addComma = false;
       if (!intrinsic.canThrow) {
@@ -629,6 +633,12 @@ EmitAttributes(const std::vector<CodeGenIntrinsic> &Ints, raw_ostream &OS) {
         OS << "Attribute::NoReturn";
         addComma = true;
       }
+      if (intrinsic.isNoDuplicate) {
+        if (addComma)
+          OS << ",";
+        OS << "Attribute::NoDuplicate";
+        addComma = true;
+      }
 
       switch (modRef) {
       case MRK_none: break;