Clean up scavengeRegister() a bit to prefer available regs, which allows

the simplification of frame index register scavenging to not have to check
for available registers directly and instead just let scavengeRegister()
handle it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107880 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 15 deletions

diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp
index d1112d3c14..3843b25370 100644
--- a/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/lib/CodeGen/PrologEpilogInserter.cpp
@@ -885,21 +885,7 @@ void PEI::scavengeFrameVirtualRegs(MachineFunction &Fn) {
             // Scavenge a new scratch register
             CurrentVirtReg = Reg;
             const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(Reg);
-            const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
-            BitVector Candidates(TRI->getNumRegs());
-            RS->getRegsAvailable(RC, Candidates);
-
-            // If there are any registers available, use the one that's
-            // unused for the longest after this instruction. That increases
-            // the ability to reuse the value.
-            if (Candidates.any()) {
-              MachineBasicBlock::iterator UMI;
-              CurrentScratchReg = RS->findSurvivorReg(I, Candidates, 25, UMI);
-            } else {
-              // No register is "free". Scavenge a register.
-              CurrentScratchReg = RS->scavengeRegister(RC, I, SPAdj);
-            }
-
+            CurrentScratchReg = RS->scavengeRegister(RC, I, SPAdj);
             PrevValue = Value;
           }
           // replace this reference to the virtual register with the