[PATCH] D34164: [PGO] Update VP metadata after memory intrinsic optimization

[Teresa Johnson via Phabricator via llvm-commits]

tejohnson created this revision.

Leave an updated VP metadata on the fallback memcpy intrinsic after
specialization. This can be used for later possible expansion based on
the average of the remaining values.


https://reviews.llvm.org/D34164

Files:
  lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
  test/Transforms/PGOProfile/memop_size_opt.ll


Index: test/Transforms/PGOProfile/memop_size_opt.ll
===================================================================
--- test/Transforms/PGOProfile/memop_size_opt.ll
+++ test/Transforms/PGOProfile/memop_size_opt.ll
@@ -38,7 +38,7 @@
 ; MEMOP_OPT:   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 1, i32 1, i1 false)
 ; MEMOP_OPT:   br label %[[MERGE_LABEL:.*]]
 ; MEMOP_OPT: [[DEFAULT_LABEL]]:
-; MEMOP_OPT:   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 %conv, i32 1, i1 false){{[[:space:]]}}
+; MEMOP_OPT:   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 %conv, i32 1, i1 false), !prof [[NEWVP:![0-9]+]]
 ; MEMOP_OPT:   br label %[[MERGE_LABEL]]
 ; MEMOP_OPT: [[MERGE_LABEL]]:
 ; MEMOP_OPT:  switch i64 %conv, label %[[DEFAULT_LABEL2:.*]] [
@@ -48,11 +48,16 @@
 ; MEMOP_OPT:   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst2, i8* %src2, i64 1, i32 1, i1 false)
 ; MEMOP_OPT:   br label %[[MERGE_LABEL2:.*]]
 ; MEMOP_OPT: [[DEFAULT_LABEL2]]:
-; MEMOP_OPT:   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst2, i8* %src2, i64 %conv, i32 1, i1 false){{[[:space:]]}}
+; MEMOP_OPT:   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst2, i8* %src2, i64 %conv, i32 1, i1 false), !prof [[NEWVP]]
 ; MEMOP_OPT:   br label %[[MERGE_LABEL2]]
 ; MEMOP_OPT: [[MERGE_LABEL2]]:
 ; MEMOP_OPT:   br label %for.inc
 ; MEMOP_OPT: [[SWITCH_BW]] = !{!"branch_weights", i32 457, i32 99}
+; Should be 457 total left (original total count 556, minus 99 from specialized
+; value 1, which is removed from VP array. Also, we only end up with 5 total
+; values, since the default max number of promotions is 5 and therefore
+; the rest of the values are ignored when extracting the VP metadata.
+; MEMOP_OPT: [[NEWVP]] = !{!"VP", i32 1, i64 457, i64 2, i64 88, i64 3, i64 77, i64 9, i64 72, i64 4, i64 66}
 
 for.inc:
   %inc = add nsw i32 %j.0, 1
Index: lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
===================================================================
--- lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
+++ lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
@@ -884,6 +884,7 @@
 
   // Keeping track of the count of the default case:
   uint64_t RemainCount = TotalCount;
+  uint64_t SavedRemainCount = SavedTotalCount;
   SmallVector<uint64_t, 16> SizeIds;
   SmallVector<uint64_t, 16> CaseCounts;
   uint64_t MaxCount = 0;
@@ -912,6 +913,8 @@
 
     assert(RemainCount >= C);
     RemainCount -= C;
+    assert(SavedRemainCount >= VD.Count);
+    SavedRemainCount -= VD.Count;
 
     if (++Version > MemOPMaxVersion && MemOPMaxVersion != 0)
       break;
@@ -968,6 +971,11 @@
 
   // Clear the value profile data.
   MI->setMetadata(LLVMContext::MD_prof, nullptr);
+  // If all promoted, we don't need the MD.prof metadata.
+  if (SavedRemainCount > 0 || Version != NumVals)
+    // Otherwise we need update with the un-promoted records back.
+    annotateValueSite(*Func.getParent(), *MI, VDs.slice(Version),
+                      SavedRemainCount, IPVK_MemOPSize, NumVals);
 
   DEBUG(dbgs() << "\n\n== Basic Block After==\n");
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D34164.102389.patch
Type: text/x-patch
Size: 3091 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170613/f42a1ccc/attachment.bin>