From 3f44bcbdcb271f8fd57a345b9bb5968b92b834a1 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Sat, 4 Mar 2017 01:34:53 +0000
Subject: [PATCH] WholeProgramDevirt: Implement exporting for uniform ret val
 opt.

Differential Revision: https://reviews.llvm.org/D29846

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296948 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/WholeProgramDevirt.cpp     | 25 +++++++++----
 .../export-uniform-ret-val.ll                 | 36 +++++++++++++++++++
 2 files changed, 55 insertions(+), 6 deletions(-)
 create mode 100644 test/Transforms/WholeProgramDevirt/export-uniform-ret-val.ll

diff --git a/lib/Transforms/IPO/WholeProgramDevirt.cpp b/lib/Transforms/IPO/WholeProgramDevirt.cpp
index bbf0a925bfc..843bd69fbd6 100644
--- a/lib/Transforms/IPO/WholeProgramDevirt.cpp
+++ b/lib/Transforms/IPO/WholeProgramDevirt.cpp
@@ -428,7 +428,8 @@ struct DevirtModule {
   void applyUniformRetValOpt(CallSiteInfo &CSInfo, StringRef FnName,
                              uint64_t TheRetVal);
   bool tryUniformRetValOpt(MutableArrayRef<VirtualCallTarget> TargetsForSlot,
-                           CallSiteInfo &CSInfo);
+                           CallSiteInfo &CSInfo,
+                           WholeProgramDevirtResolution::ByArg *Res);
 
   void applyUniqueRetValOpt(CallSiteInfo &CSInfo, StringRef FnName, bool IsOne,
                             Constant *UniqueMemberAddr);
@@ -439,7 +440,8 @@ struct DevirtModule {
   void applyVirtualConstProp(CallSiteInfo &CSInfo, StringRef FnName,
                              Constant *Byte, Constant *Bit);
   bool tryVirtualConstProp(MutableArrayRef<VirtualCallTarget> TargetsForSlot,
-                           VTableSlotInfo &SlotInfo);
+                           VTableSlotInfo &SlotInfo,
+                           WholeProgramDevirtResolution *Res);
 
   void rebuildGlobal(VTableBits &B);
 
@@ -727,10 +729,12 @@ void DevirtModule::applyUniformRetValOpt(CallSiteInfo &CSInfo, StringRef FnName,
     Call.replaceAndErase(
         "uniform-ret-val", FnName, RemarksEnabled,
         ConstantInt::get(cast<IntegerType>(Call.CS.getType()), TheRetVal));
+  CSInfo.TypeCheckedLoadUsers.clear();
 }
 
 bool DevirtModule::tryUniformRetValOpt(
-    MutableArrayRef<VirtualCallTarget> TargetsForSlot, CallSiteInfo &CSInfo) {
+    MutableArrayRef<VirtualCallTarget> TargetsForSlot, CallSiteInfo &CSInfo,
+    WholeProgramDevirtResolution::ByArg *Res) {
   // Uniform return value optimization. If all functions return the same
   // constant, replace all calls with that constant.
   uint64_t TheRetVal = TargetsForSlot[0].RetVal;
@@ -738,6 +742,11 @@ bool DevirtModule::tryUniformRetValOpt(
     if (Target.RetVal != TheRetVal)
       return false;
 
+  if (CSInfo.isExported()) {
+    Res->TheKind = WholeProgramDevirtResolution::ByArg::UniformRetVal;
+    Res->Info = TheRetVal;
+  }
+
   applyUniformRetValOpt(CSInfo, TargetsForSlot[0].Fn->getName(), TheRetVal);
   if (RemarksEnabled)
     for (auto &&Target : TargetsForSlot)
@@ -824,7 +833,7 @@ void DevirtModule::applyVirtualConstProp(CallSiteInfo &CSInfo, StringRef FnName,
 
 bool DevirtModule::tryVirtualConstProp(
     MutableArrayRef<VirtualCallTarget> TargetsForSlot,
-    VTableSlotInfo &SlotInfo) {
+    VTableSlotInfo &SlotInfo, WholeProgramDevirtResolution *Res) {
   // This only works if the function returns an integer.
   auto RetType = dyn_cast<IntegerType>(TargetsForSlot[0].Fn->getReturnType());
   if (!RetType)
@@ -856,7 +865,11 @@ bool DevirtModule::tryVirtualConstProp(
     if (!tryEvaluateFunctionsWithArgs(TargetsForSlot, CSByConstantArg.first))
       continue;
 
-    if (tryUniformRetValOpt(TargetsForSlot, CSByConstantArg.second))
+    WholeProgramDevirtResolution::ByArg *ResByArg = nullptr;
+    if (Res)
+      ResByArg = &Res->ResByArg[CSByConstantArg.first];
+
+    if (tryUniformRetValOpt(TargetsForSlot, CSByConstantArg.second, ResByArg))
       continue;
 
     if (tryUniqueRetValOpt(BitWidth, TargetsForSlot, CSByConstantArg.second))
@@ -1175,7 +1188,7 @@ bool DevirtModule::run() {
                  .WPDRes[S.first.ByteOffset];
 
       if (!trySingleImplDevirt(TargetsForSlot, S.second, Res) &&
-          tryVirtualConstProp(TargetsForSlot, S.second))
+          tryVirtualConstProp(TargetsForSlot, S.second, Res))
         DidVirtualConstProp = true;
 
       // Collect functions devirtualized at least for one call site for stats.
diff --git a/test/Transforms/WholeProgramDevirt/export-uniform-ret-val.ll b/test/Transforms/WholeProgramDevirt/export-uniform-ret-val.ll
new file mode 100644
index 00000000000..1d7030c41fd
--- /dev/null
+++ b/test/Transforms/WholeProgramDevirt/export-uniform-ret-val.ll
@@ -0,0 +1,36 @@
+; RUN: opt -wholeprogramdevirt -wholeprogramdevirt-summary-action=export -wholeprogramdevirt-read-summary=%S/Inputs/export.yaml -wholeprogramdevirt-write-summary=%t -S -o - %s | FileCheck %s
+; RUN: FileCheck --check-prefix=SUMMARY %s < %t
+
+; SUMMARY:     - TypeTests:
+; SUMMARY-NEXT:  TypeTestAssumeVCalls:
+
+; SUMMARY:      TypeIdMap:
+; SUMMARY-NEXT:   typeid4:
+; SUMMARY-NEXT:     TTRes:
+; SUMMARY-NEXT:       Kind:            Unsat
+; SUMMARY-NEXT:       SizeM1BitWidth:  0
+; SUMMARY-NEXT:     WPDRes:
+; SUMMARY-NEXT:       0:
+; SUMMARY-NEXT:         Kind:            Indir
+; SUMMARY-NEXT:         SingleImplName:  ''
+; SUMMARY-NEXT:         ResByArg:
+; SUMMARY-NEXT:           24,12:
+; SUMMARY-NEXT:             Kind:            UniformRetVal
+; SUMMARY-NEXT:             Info:            36
+
+; CHECK: @vt4a = constant i32 (i8*, i32, i32)* @vf4a
+@vt4a = constant i32 (i8*, i32, i32)* @vf4a, !type !0
+
+; CHECK: @vt4b = constant i32 (i8*, i32, i32)* @vf4b
+@vt4b = constant i32 (i8*, i32, i32)* @vf4b, !type !0
+
+define i32 @vf4a(i8*, i32 %x, i32 %y) {
+  %z = add i32 %x, %y
+  ret i32 %z
+}
+
+define i32 @vf4b(i8*, i32 %x, i32 %y) {
+  ret i32 36
+}
+
+!0 = !{i32 0, !"typeid4"}
-- 
2.50.1