Update profile during memory instrinsic optimization

Summary:
Ensure that the new merge BB (which contains the rest of the original BB
after the mem op being optimized) gets a profile frequency, in case
there are additional mem ops later in the BB. Otherwise they get skipped
as the merge BB looks cold.

Reviewers: davidxl, xur

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32447

llvm-svn: 301244

2 files changed, 19 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp b/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
index 61d627673c9..d7eb857cff7 100644
--- a/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
+++ b/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
@@ -943,14 +943,16 @@ bool MemOPSizeOpt::perform(MemIntrinsic *MI) {
   BasicBlock *BB = MI->getParent();
   DEBUG(dbgs() << "\n\n== Basic Block Before ==\n");
   DEBUG(dbgs() << *BB << "\n");
+  auto OrigBBFreq = BFI.getBlockFreq(BB);
 
   BasicBlock *DefaultBB = SplitBlock(BB, MI);
   BasicBlock::iterator It(*MI);
   ++It;
   assert(It != DefaultBB->end());
   BasicBlock *MergeBB = SplitBlock(DefaultBB, &(*It));
-  DefaultBB->setName("MemOP.Default");
   MergeBB->setName("MemOP.Merge");
+  BFI.setBlockFreq(MergeBB, OrigBBFreq.getFrequency());
+  DefaultBB->setName("MemOP.Default");
 
   auto &Ctx = Func.getContext();
   IRBuilder<> IRB(BB);
diff --git a/llvm/test/Transforms/PGOProfile/memop_size_opt.ll b/llvm/test/Transforms/PGOProfile/memop_size_opt.ll
index c7c42f3c1d3..19a2b7ed293 100644
--- a/llvm/test/Transforms/PGOProfile/memop_size_opt.ll
+++ b/llvm/test/Transforms/PGOProfile/memop_size_opt.ll
@@ -4,7 +4,7 @@
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-define void @foo(i8* %dst, i8* %src, i32* %a, i32 %n) !prof !27 {
+define void @foo(i8* %dst, i8* %src, i8* %dst2, i8* %src2, i32* %a, i32 %n) !prof !27 {
 entry:
   br label %for.cond
 
@@ -28,19 +28,29 @@ for.body3:
   %add = add nsw i32 %i.0, 1
   %conv = sext i32 %add to i64
   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 %conv, i32 1, i1 false), !prof !30
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst2, i8* %src2, i64 %conv, i32 1, i1 false), !prof !31
   br label %for.inc
 
-; MEMOP_OPT:  switch i64 %conv, label %[[Default_LABEL:.*]] [
+; MEMOP_OPT:  switch i64 %conv, label %[[DEFAULT_LABEL:.*]] [
 ; MEMOP_OPT:    i64 1, label %[[CASE_1_LABEL:.*]]
 ; MEMOP_OPT:  ], !prof [[SWITCH_BW:![0-9]+]] 
 ; MEMOP_OPT: [[CASE_1_LABEL]]:
 ; 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)
-; MEMOP_OPT-NOT:   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 %conv, i32 1, i1 false), !prof
+; 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:   br label %[[MERGE_LABEL]]
 ; MEMOP_OPT: [[MERGE_LABEL]]:
+; MEMOP_OPT:  switch i64 %conv, label %[[DEFAULT_LABEL2:.*]] [
+; MEMOP_OPT:    i64 1, label %[[CASE_1_LABEL2:.*]]
+; MEMOP_OPT:  ], !prof [[SWITCH_BW:![0-9]+]] 
+; MEMOP_OPT: [[CASE_1_LABEL2]]:
+; 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:   br label %[[MERGE_LABEL2]]
+; MEMOP_OPT: [[MERGE_LABEL2]]:
 ; MEMOP_OPT:   br label %for.inc
 ; MEMOP_OPT: [[SWITCH_BW]] = !{!"branch_weights", i32 457, i32 99}
 
@@ -92,6 +102,7 @@ for.end6:
 !28 = !{!"branch_weights", i32 20, i32 1}
 !29 = !{!"branch_weights", i32 556, i32 20}
 !30 = !{!"VP", i32 1, i64 556, i64 1, i64 99, i64 2, i64 88, i64 3, i64 77, i64 9, i64 72, i64 4, i64 66, i64 5, i64 55, i64 6, i64 44, i64 7, i64 33, i64 8, i64 22}
+!31 = !{!"VP", i32 1, i64 556, i64 1, i64 99, i64 2, i64 88, i64 3, i64 77, i64 9, i64 72, i64 4, i64 66, i64 5, i64 55, i64 6, i64 44, i64 7, i64 33, i64 8, i64 22}
 
 declare void @llvm.lifetime.start(i64, i8* nocapture)