[AMDGPU] Disable SReg Global LD/ST, perf regression

Differential Revision: https://reviews.llvm.org/D55093

llvm-svn: 348014

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIFixupVectorISel.cpp b/llvm/lib/Target/AMDGPU/SIFixupVectorISel.cpp
index 3da043f3709..ee39eb04d83 100644
--- a/llvm/lib/Target/AMDGPU/SIFixupVectorISel.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFixupVectorISel.cpp
@@ -43,6 +43,11 @@
 
 using namespace llvm;
 
+static cl::opt<bool> EnableGlobalSGPRAddr(
+  "amdgpu-enable-global-sgpr-addr",
+  cl::desc("Enable use of SGPR regs for GLOBAL LOAD/STORE instructions"),
+  cl::init(false));
+
 STATISTIC(NumSGPRGlobalOccurs, "Number of global ld/st opportunities");
 STATISTIC(NumSGPRGlobalSaddrs, "Number of global sgpr instructions converted");
 
@@ -155,6 +160,8 @@ static bool fixupGlobalSaddr(MachineBasicBlock &MBB,
                              const GCNSubtarget &ST,
                              const SIInstrInfo *TII,
                              const SIRegisterInfo *TRI) {
+  if (!EnableGlobalSGPRAddr)
+    return false;
   bool FuncModified = false;
   MachineBasicBlock::iterator I, Next;
   for (I = MBB.begin(); I != MBB.end(); I = Next) {