[AArch64][Falkor] Ignore SP based loads in HW prefetch fixups.

Reviewers: mcrosier

Subscribers: aemerson, rengolin, javed.absar, kristof.beyls

Differential Revision: https://reviews.llvm.org/D38301

llvm-svn: 314319

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64FalkorHWPFFix.cpp b/llvm/lib/Target/AArch64/AArch64FalkorHWPFFix.cpp
index 6df8df0e65a..3acacf7ce58 100644
--- a/llvm/lib/Target/AArch64/AArch64FalkorHWPFFix.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FalkorHWPFFix.cpp
@@ -638,9 +638,14 @@ static Optional<LoadInfo> getLoadInfo(const MachineInstr &MI) {
     break;
   }
 
+  // Loads from the stack pointer don't get prefetched.
+  unsigned BaseReg = MI.getOperand(BaseRegIdx).getReg();
+  if (BaseReg == AArch64::SP || BaseReg == AArch64::WSP)
+    return None;
+
   LoadInfo LI;
   LI.DestReg = DestRegIdx == -1 ? 0 : MI.getOperand(DestRegIdx).getReg();
-  LI.BaseReg = MI.getOperand(BaseRegIdx).getReg();
+  LI.BaseReg = BaseReg;
   LI.BaseRegIdx = BaseRegIdx;
   LI.OffsetOpnd = OffsetIdx == -1 ? nullptr : &MI.getOperand(OffsetIdx);
   LI.IsPrePost = IsPrePost;