PrologEpilogInserter: Rewrite API to determine callee save regsiters.

This changes TargetFrameLowering::processFunctionBeforeCalleeSavedScan():

- Rename the function to determineCalleeSaves()
- Pass a bitset of callee saved registers by reference, thus avoiding
  the function-global PhysRegUsed bitset in MachineRegisterInfo.
- Without PhysRegUsed the implementation is fine tuned to not save
  physcial registers which are only read but never modified.

Related to rdar://21539507

Differential Revision: http://reviews.llvm.org/D10909

llvm-svn: 242165

1 files changed, 2 insertions, 4 deletions

diff --git a/llvm/test/CodeGen/ARM/arm-returnaddr.ll b/llvm/test/CodeGen/ARM/arm-returnaddr.ll
index 4266572b077..26f8c67bb15 100644
--- a/llvm/test/CodeGen/ARM/arm-returnaddr.ll
+++ b/llvm/test/CodeGen/ARM/arm-returnaddr.ll
@@ -8,7 +8,6 @@
 define i8* @rt0(i32 %x) nounwind readnone {
 entry:
 ; CHECK-LABEL: rt0:
-; CHECK: {r7, lr}
 ; CHECK: mov r0, lr
   %0 = tail call i8* @llvm.returnaddress(i32 0)
   ret i8* %0
@@ -17,10 +16,9 @@ entry:
 define i8* @rt2() nounwind readnone {
 entry:
 ; CHECK-LABEL: rt2:
-; CHECK: {r7, lr}
 ; CHECK: ldr r[[R0:[0-9]+]], [r7]
-; CHECK: ldr r0, [r0]
-; CHECK: ldr r0, [r0, #4]
+; CHECK: ldr r0, [r[[R0]]]
+; CHECK: ldr r0, [r[[R0]], #4]
   %0 = tail call i8* @llvm.returnaddress(i32 2)
   ret i8* %0
 }