[llvm] r320848 - [Memcpy Loop Lowering] Insert loop BB inbetween the split BB.

[Sean Fertile via llvm-commits]

Author: sfertile
Date: Fri Dec 15 11:29:12 2017
New Revision: 320848

URL: http://llvm.org/viewvc/llvm-project?rev=320848&view=rev
Log:
[Memcpy Loop Lowering] Insert loop BB inbetween the split BB.

The original memcpy expansion inserted the loop basic block inbetween
the 2 new basic blocks created by splitting the original block the memcpy
call was in. This commit makes the new memcpy expansion do the same to keep the
layout of the IR matching between the old and new implementations.

Differential Review: https://reviews.llvm.org/D41197

Modified:
    llvm/trunk/lib/Transforms/Utils/LowerMemIntrinsics.cpp
    llvm/trunk/test/CodeGen/NVPTX/lower-aggr-copies.ll

Modified: llvm/trunk/lib/Transforms/Utils/LowerMemIntrinsics.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LowerMemIntrinsics.cpp?rev=320848&r1=320847&r2=320848&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LowerMemIntrinsics.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LowerMemIntrinsics.cpp Fri Dec 15 11:29:12 2017
@@ -174,7 +174,7 @@ void llvm::createMemCpyLoopUnknownSize(I
   Value *RuntimeBytesCopied = PLBuilder.CreateSub(CopyLen, RuntimeResidual);
 
   BasicBlock *LoopBB =
-      BasicBlock::Create(Ctx, "loop-memcpy-expansion", ParentFunc, nullptr);
+      BasicBlock::Create(Ctx, "loop-memcpy-expansion", ParentFunc, PostLoopBB);
   IRBuilder<> LoopBuilder(LoopBB);
 
   PHINode *LoopIndex = LoopBuilder.CreatePHI(CopyLenType, 2, "loop-index");
@@ -193,7 +193,8 @@ void llvm::createMemCpyLoopUnknownSize(I
   if (LoopOpType != Int8Type) {
     // Loop body for the residual copy.
     BasicBlock *ResLoopBB = BasicBlock::Create(Ctx, "loop-memcpy-residual",
-                                               PreLoopBB->getParent(), nullptr);
+                                               PreLoopBB->getParent(),
+                                               PostLoopBB);
     // Residual loop header.
     BasicBlock *ResHeaderBB = BasicBlock::Create(
         Ctx, "loop-memcpy-residual-header", PreLoopBB->getParent(), nullptr);

Modified: llvm/trunk/test/CodeGen/NVPTX/lower-aggr-copies.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/NVPTX/lower-aggr-copies.ll?rev=320848&r1=320847&r2=320848&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/NVPTX/lower-aggr-copies.ll (original)
+++ llvm/trunk/test/CodeGen/NVPTX/lower-aggr-copies.ll Fri Dec 15 11:29:12 2017
@@ -50,6 +50,9 @@ entry:
 ; WIR:         [[IndexInc]] = add i64 %loop-index, 1
 ; WIR:         [[Cond2:%[0-9]+]] = icmp ult i64 [[IndexInc]], [[LoopCount]]
 ; WIR:         br i1 [[Cond2]], label %loop-memcpy-expansion, label %post-loop-memcpy-expansion
+
+; WIR-LABEL:   post-loop-memcpy-expansion:
+; WIR:         ret i8* %dst
 }
 
 define i8* @memcpy_volatile_caller(i8* %dst, i8* %src, i64 %n) #0 {
@@ -85,6 +88,9 @@ entry:
 ; WIR:         [[IndexInc]] = add i64 %loop-index, 1
 ; WIR:         [[Cond2:%[0-9]+]] = icmp ult i64 [[IndexInc]], [[LoopCount]]
 ; WIR:         br i1 [[Cond2]], label %loop-memcpy-expansion, label %post-loop-memcpy-expansion
+
+; WIR-LABEL:   post-loop-memcpy-expansion:
+; WIR:         ret i8* %dst
 }
 
 define i8* @memcpy_casting_caller(i32* %dst, i32* %src, i64 %n) #0 {