Bug 18149: [AArch32] VSel instructions has no ARMCC field

The current peephole optimizing for compare inst assumes an instr that
uses CPSR has an MO for ARM Cond code.However, for VSEL instructions
(vseqeq, vselgt, vselgt, vselvs), there is no such operand nor do
they support the modification of Cond Code.

llvm-svn: 196588

1 files changed, 34 insertions, 7 deletions

diff --git a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
index 06cef6d603b..c532229dd91 100644
--- a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -2374,8 +2374,32 @@ optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg, unsigned SrcReg2,
           isSafe = true;
           break;
         }
-        // Condition code is after the operand before CPSR.
-        ARMCC::CondCodes CC = (ARMCC::CondCodes)Instr.getOperand(IO-1).getImm();
+        // Condition code is after the operand before CPSR except for VSELs.
+        ARMCC::CondCodes CC;
+        bool IsInstrVSel = true;
+        switch (Instr.getOpcode()) {
+        default:
+          IsInstrVSel = false;
+          CC = (ARMCC::CondCodes)Instr.getOperand(IO - 1).getImm();
+          break;
+        case ARM::VSELEQD:
+        case ARM::VSELEQS:
+          CC = ARMCC::EQ;
+          break;
+        case ARM::VSELGTD:
+        case ARM::VSELGTS:
+          CC = ARMCC::GT;
+          break;
+        case ARM::VSELGED:
+        case ARM::VSELGES:
+          CC = ARMCC::GE;
+          break;
+        case ARM::VSELVSS:
+        case ARM::VSELVSD:
+          CC = ARMCC::VS;
+          break;
+        }
+
         if (Sub) {
           ARMCC::CondCodes NewCC = getSwappedCondition(CC);
           if (NewCC == ARMCC::AL)
@@ -2386,11 +2410,14 @@ optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg, unsigned SrcReg2,
           // If it is safe to remove CmpInstr, the condition code of these
           // operands will be modified.
           if (SrcReg2 != 0 && Sub->getOperand(1).getReg() == SrcReg2 &&
-              Sub->getOperand(2).getReg() == SrcReg)
-            OperandsToUpdate.push_back(std::make_pair(&((*I).getOperand(IO-1)),
-                                                      NewCC));
-        }
-        else
+              Sub->getOperand(2).getReg() == SrcReg) {
+            // VSel doesn't support condition code update.
+            if (IsInstrVSel)
+              return false;
+            OperandsToUpdate.push_back(
+                std::make_pair(&((*I).getOperand(IO - 1)), NewCC));
+          }
+        } else
           switch (CC) {
           default:
             // CPSR can be used multiple times, we should continue.