Re-enable register pressure aware machine licm with fixes. Hoist() may have

erased the instruction during LICM so UpdateRegPressureAfter() should not
reference it afterwards.

llvm-svn: 116845

1 files changed, 20 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
index aca292abea5..0b5b2437abc 100644
--- a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -1925,3 +1925,23 @@ ARMBaseInstrInfo::getOperandLatency(const InstrItineraryData *ItinData,
   return getOperandLatency(ItinData, DefTID, DefIdx, DefAlign,
                            UseTID, UseIdx, UseAlign);
 }
+
+bool ARMBaseInstrInfo::
+hasHighOperandLatency(const InstrItineraryData *ItinData,
+                      const MachineRegisterInfo *MRI,
+                      const MachineInstr *DefMI, unsigned DefIdx,
+                      const MachineInstr *UseMI, unsigned UseIdx) const {
+  unsigned DDomain = DefMI->getDesc().TSFlags & ARMII::DomainMask;
+  unsigned UDomain = UseMI->getDesc().TSFlags & ARMII::DomainMask;
+  if (Subtarget.isCortexA8() &&
+      (DDomain == ARMII::DomainVFP || UDomain == ARMII::DomainVFP))
+    // CortexA8 VFP instructions are not pipelined.
+    return true;
+
+  // Hoist VFP / NEON instructions with 4 or higher latency.
+  int Latency = getOperandLatency(ItinData, DefMI, DefIdx, UseMI, UseIdx);
+  if (Latency <= 3)
+    return false;
+  return DDomain == ARMII::DomainVFP || DDomain == ARMII::DomainNEON ||
+         UDomain == ARMII::DomainVFP || UDomain == ARMII::DomainNEON;
+}