[MachineSink] Use SkipPHIsAndLabels for sink insertion points

For AMDGPU the insertion point for a block may not be the first
non-PHI instruction.  This happens when a block contains EXEC
mask manipulation related to control flow (converging lanes).

Use SkipPHIsAndLabels to determine the block insertion point
so that the target can skip any block prologue instructions.

Reviewed By: rampitec, ruiling

Differential Revision: https://reviews.llvm.org/D119399

1 files changed, 6 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp
index e584ebe..7ed33f9 100644
--- a/llvm/lib/CodeGen/MachineSink.cpp
+++ b/llvm/lib/CodeGen/MachineSink.cpp
@@ -1272,7 +1272,8 @@ bool MachineSinking::SinkIntoLoop(MachineLoop *L, MachineInstr &I) {
   }
 
   LLVM_DEBUG(dbgs() << "LoopSink: Sinking instruction!\n");
-  SinkBlock->splice(SinkBlock->getFirstNonPHI(), Preheader, I);
+  SinkBlock->splice(SinkBlock->SkipPHIsAndLabels(SinkBlock->begin()), Preheader,
+                    I);
 
   // The instruction is moved from its basic block, so do not retain the
   // debug information.
@@ -1392,9 +1393,8 @@ bool MachineSinking::SinkInstruction(MachineInstr &MI, bool &SawStore,
   }
 
   // Determine where to insert into. Skip phi nodes.
-  MachineBasicBlock::iterator InsertPos = SuccToSinkTo->begin();
-  while (InsertPos != SuccToSinkTo->end() && InsertPos->isPHI())
-    ++InsertPos;
+  MachineBasicBlock::iterator InsertPos =
+      SuccToSinkTo->SkipPHIsAndLabels(SuccToSinkTo->begin());
 
   // Collect debug users of any vreg that this inst defines.
   SmallVector<MIRegs, 4> DbgUsersToSink;
@@ -1796,7 +1796,8 @@ bool PostRAMachineSinking::tryToSinkCopy(MachineBasicBlock &CurBB,
     // Clear the kill flag if SrcReg is killed between MI and the end of the
     // block.
     clearKillFlags(&MI, CurBB, UsedOpsInCopy, UsedRegUnits, TRI);
-    MachineBasicBlock::iterator InsertPos = SuccBB->getFirstNonPHI();
+    MachineBasicBlock::iterator InsertPos =
+        SuccBB->SkipPHIsAndLabels(SuccBB->begin());
     performSink(MI, *SuccBB, InsertPos, DbgValsToSink);
     updateLiveIn(&MI, SuccBB, UsedOpsInCopy, DefedRegsInCopy);