Anti-dependency breaking needs to be careful not to use reserved regs

llvm-svn: 112832

2 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp b/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp
index 62e40e9636b..5a634d6ccb0 100644
--- a/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp
+++ b/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp
@@ -654,6 +654,8 @@ bool AggressiveAntiDepBreaker::FindSuitableFreeRegisters(
     if (R == RB) R = RE;
     --R;
     const unsigned NewSuperReg = *R;
+    // Don't consider non-allocatable registers
+    if (!AllocatableSet.test(NewSuperReg)) continue;
     // Don't replace a register with itself.
     if (NewSuperReg == SuperReg) continue;
 
diff --git a/llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp b/llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp
index 98d4d413201..335d2d8e9ba 100644
--- a/llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp
+++ b/llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp
@@ -330,6 +330,8 @@ CriticalAntiDepBreaker::findSuitableFreeRegister(MachineInstr *MI,
   for (TargetRegisterClass::iterator R = RC->allocation_order_begin(MF),
        RE = RC->allocation_order_end(MF); R != RE; ++R) {
     unsigned NewReg = *R;
+    // Don't consider non-allocatable registers
+    if (!AllocatableSet.test(NewReg)) continue;
     // Don't replace a register with itself.
     if (NewReg == AntiDepReg) continue;
     // Don't replace a register with one that was recently used to repair