File backport-llvm-r204200 of Package llvm

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File backport-llvm-r204200 of Package llvm

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r204200 | eliben | 2014-03-19 00:51:07 +0100 (Wed, 19 Mar 2014) | 11 lines

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.

------------------------------------------------------------------------
Index: utils/TableGen/IntrinsicEmitter.cpp
===================================================================
--- utils/TableGen/IntrinsicEmitter.cpp.orig
+++ utils/TableGen/IntrinsicEmitter.cpp
@@ -515,6 +515,9 @@ 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;
 
@@ -629,7 +632,8 @@ EmitAttributes(const std::vector<CodeGen
 
     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) {
@@ -642,6 +646,12 @@ EmitAttributes(const std::vector<CodeGen
         OS << "Attribute::NoReturn";
         addComma = true;
       }
+      if (intrinsic.isNoDuplicate) {
+        if (addComma)
+          OS << ",";
+        OS << "Attribute::NoDuplicate";
+        addComma = true;
+      }
 
       switch (modRef) {
       case MRK_none: break;
Index: utils/TableGen/CodeGenTarget.cpp
===================================================================
--- utils/TableGen/CodeGenTarget.cpp.orig
+++ utils/TableGen/CodeGenTarget.cpp
@@ -430,6 +430,7 @@ CodeGenIntrinsic::CodeGenIntrinsic(Recor
   isCommutative = false;
   canThrow = false;
   isNoReturn = false;
+  isNoDuplicate = false;
 
   if (DefName.size() <= 4 ||
       std::string(DefName.begin(), DefName.begin() + 4) != "int_")
@@ -554,6 +555,8 @@ CodeGenIntrinsic::CodeGenIntrinsic(Recor
       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")) {
Index: utils/TableGen/CodeGenIntrinsics.h
===================================================================
--- utils/TableGen/CodeGenIntrinsics.h.orig
+++ 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;
 
Index: test/Feature/intrinsic-noduplicate.ll
===================================================================
--- /dev/null
+++ 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 }
Index: test/CodeGen/NVPTX/noduplicate-syncthreads.ll
===================================================================
--- /dev/null
+++ 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}
Index: include/llvm/IR/Intrinsics.td
===================================================================
--- include/llvm/IR/Intrinsics.td.orig
+++ include/llvm/IR/Intrinsics.td
@@ -69,6 +69,10 @@ class ReadNone<int argNo> : IntrinsicPro
 
 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.
 //===----------------------------------------------------------------------===//
Index: include/llvm/IR/IntrinsicsNVVM.td
===================================================================
--- include/llvm/IR/IntrinsicsNVVM.td.orig
+++ include/llvm/IR/IntrinsicsNVVM.td
@@ -730,15 +730,15 @@ def llvm_anyi64ptr_ty     : LLVMAnyPoint
 
 // 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">,

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