1 files changed, 32 insertions, 7 deletions

diff --git a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
index bee5bfd7b2e..37290ad9746 100644
--- a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -520,11 +520,40 @@ bool ARMBaseInstrInfo::DefinesPredicate(MachineInstr *MI,
 
 static bool isCPSRDefined(const MachineInstr *MI) {
   for (const auto &MO : MI->operands())
-    if (MO.isReg() && MO.getReg() == ARM::CPSR && (MO.isDef() || !MO.isDead()))
+    if (MO.isReg() && MO.getReg() == ARM::CPSR && MO.isDef())
       return true;
   return false;
 }
 
+static bool isEligibleForITBlock(const MachineInstr *MI) {
+  switch (MI->getOpcode()) {
+  default: return true;
+  case ARM::tADC:   // ADC (register) T1
+  case ARM::tADDi3: // ADD (immediate) T1
+  case ARM::tADDi8: // ADD (immediate) T2
+  case ARM::tADDrr: // ADD (register) T1
+  case ARM::tAND:   // AND (register) T1
+  case ARM::tASRri: // ASR (immediate) T1
+  case ARM::tASRrr: // ASR (register) T1
+  case ARM::tBIC:   // BIC (register) T1
+  case ARM::tEOR:   // EOR (register) T1
+  case ARM::tLSLri: // LSL (immediate) T1
+  case ARM::tLSLrr: // LSL (register) T1
+  case ARM::tLSRri: // LSR (immediate) T1
+  case ARM::tLSRrr: // LSR (register) T1
+  case ARM::tMUL:   // MUL T1
+  case ARM::tMVN:   // MVN (register) T1
+  case ARM::tORR:   // ORR (register) T1
+  case ARM::tROR:   // ROR (register) T1
+  case ARM::tRSB:   // RSB (immediate) T1
+  case ARM::tSBC:   // SBC (register) T1
+  case ARM::tSUBi3: // SUB (immediate) T1
+  case ARM::tSUBi8: // SUB (immediate) T2
+  case ARM::tSUBrr: // SUB (register) T1
+    return !isCPSRDefined(MI);
+  }
+}
+
 /// isPredicable - Return true if the specified instruction can be predicated.
 /// By default, this returns true for every instruction with a
 /// PredicateOperand.
@@ -532,12 +561,8 @@ bool ARMBaseInstrInfo::isPredicable(MachineInstr *MI) const {
   if (!MI->isPredicable())
     return false;
 
-  // The ARM Architecture Reference Manual states that the CPSR may only be
-  // accessed by MUL in Thumb mode if it is outside an IT block.  Thus, if CPSR
-  // is defined (or clobbered) by this instruction, it is not predicable.
-  if (MI->getOpcode() == ARM::tMUL || MI->getOpcode() == ARM::t2MUL)
-    if (isCPSRDefined(MI))
-      return false;
+  if (!isEligibleForITBlock(MI))
+    return false;
 
   ARMFunctionInfo *AFI =
     MI->getParent()->getParent()->getInfo<ARMFunctionInfo>();