[PATCH] D31143: Set the prof weight correctly for call instructions in DeadArgumentElimination.

[Dehao Chen via Phabricator via llvm-commits]

danielcdh created this revision.

In DeadArgumentElimination, the call instructions will be replaced. We also need to set the prof weights so that function inlining can find the correct profile.


https://reviews.llvm.org/D31143

Files:
  include/llvm/IR/Instruction.h
  lib/IR/Instruction.cpp
  lib/Transforms/IPO/DeadArgumentElimination.cpp
  test/Transforms/DeadArgElim/prof.ll


Index: test/Transforms/DeadArgElim/prof.ll
===================================================================
--- /dev/null
+++ test/Transforms/DeadArgElim/prof.ll
@@ -0,0 +1,18 @@
+; RUN: opt -deadargelim -S < %s | FileCheck %s
+
+; Checks if !prof metadata is reserved in deadargelim.
+
+; Function Attrs: uwtable
+define void @_Z2f2v() #0 {
+; CHECK: call void @_ZL2f1iz(), !prof ![[PROF:[0-9]]]
+  call void (i32, ...) @_ZL2f1iz(i32 1), !prof !0
+  ret void
+}
+
+; Function Attrs: nounwind uwtable
+define internal void @_ZL2f1iz(i32, ...) #1 {
+  ret void
+}
+
+; CHECK:![[PROF]] = !{!"branch_weights", i32 30}
+!0 = !{!"branch_weights", i32 30}
Index: lib/Transforms/IPO/DeadArgumentElimination.cpp
===================================================================
--- lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -194,6 +194,9 @@
           cast<CallInst>(Call)->getTailCallKind());
     }
     New->setDebugLoc(Call->getDebugLoc());
+    uint64_t W;
+    if (Call->extractProfTotalWeight(W))
+      New->setProfWeight(W);
 
     Args.clear();
 
@@ -900,6 +903,9 @@
           cast<CallInst>(Call)->getTailCallKind());
     }
     New->setDebugLoc(Call->getDebugLoc());
+    uint64_t W;
+    if (Call->extractProfTotalWeight(W))
+      New->setProfWeight(W);
 
     Args.clear();
 
Index: lib/IR/Instruction.cpp
===================================================================
--- lib/IR/Instruction.cpp
+++ lib/IR/Instruction.cpp
@@ -652,3 +652,14 @@
   MDBuilder MDB(getContext());
   setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
 }
+
+void Instruction::setProfWeight(uint64_t W) {
+  assert((isa<CallInst>(this) || isa<InvokeInst>(this)) &&
+         "Can only set weights for call instruciton");
+  if (W == 0)
+    return;
+  SmallVector<uint32_t, 1> Weights;
+  Weights.push_back(W);
+  MDBuilder MDB(getContext());
+  setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
+}
Index: include/llvm/IR/Instruction.h
===================================================================
--- include/llvm/IR/Instruction.h
+++ include/llvm/IR/Instruction.h
@@ -255,6 +255,9 @@
   /// Updates branch_weights metadata by scaling it by \p S / \p T.
   void updateProfWeight(uint64_t S, uint64_t T);
 
+  /// Sets the branch_weights metadata to \p W for CallInst.
+  void setProfWeight(uint64_t W);
+
   /// Set the debug location information for this instruction.
   void setDebugLoc(DebugLoc Loc) { DbgLoc = std::move(Loc); }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D31143.92362.patch
Type: text/x-patch
Size: 2533 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170320/6275f256/attachment-0001.bin>