Only allocate non-volatile registers R13-31 (for now).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14500 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCRegisterInfo.td b/lib/Target/PowerPC/PPCRegisterInfo.td
index d6aaf4b..da7152e 100644 (file)
--- a/lib/Target/PowerPC/PPCRegisterInfo.td
+++ b/lib/Target/PowerPC/PPCRegisterInfo.td
@@ -73,9 +73,17 @@ def TBL : SPR<4>;
 def TBU : SPR<5>;
 
 /// Register classes: one for floats and another for non-floats.
-def GPRC : RegisterClass<i32, 4, [R0, R1, R2, R3, R4, R5, R6, R7,
-  R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21,
-  R22, R23, R24, R25, R26, R27, R28, R29, R30, R31]>;
+def GPRC : RegisterClass<i32, 4, [R13, R14, R15, R16, R17, R18, R19, R20, R21,
+                                  R22, R23, R24, R25, R26, R27, R28, R29, R30, 
+                                  R31, R0, R1, R2, R3, R4, R5, R6, R7,
+                                  R8, R9, R10, R11, R12]> {
+  let Methods = [{
+    iterator allocation_order_end(MachineFunction &MF) const {
+      return end()-13;   // do not allocate r0-r12
+    }
+  }];
+}
+
 def FPRC : RegisterClass<f64, 8, [F0, F1, F2, F3, F4, F5, F6, F7,
   F8, F9, F10, F11, F12, F13, F14, F15, F16, F17, F18, F19, F20, F21,
   F22, F23, F24, F25, F26, F27, F28, F29, F30, F31]>;