Fix PR7372: Conditional branches (at least on ARM) are treated as predicated,

[oota-llvm.git] / lib / CodeGen / LiveVariables.cpp

diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index 079684eea0799dd9d77be6dbd6d025900c277f93..41b891d30f23b3ca0aaaf4acaa90f53d1d260dbe 100644 (file)
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -286,7 +286,7 @@ MachineInstr *LiveVariables::FindLastRefOrPartRef(unsigned Reg) {
   MachineInstr *LastDef = PhysRegDef[Reg];
   MachineInstr *LastUse = PhysRegUse[Reg];
   if (!LastDef && !LastUse)
-    return false;
+    return 0;
 
   MachineInstr *LastRefOrPartRef = LastUse ? LastUse : LastDef;
   unsigned LastRefOrPartRefDist = DistanceMap[LastRefOrPartRef];
@@ -609,7 +609,12 @@ bool LiveVariables::runOnMachineFunction(MachineFunction &mf) {
 
     // Finally, if the last instruction in the block is a return, make sure to
     // mark it as using all of the live-out values in the function.
-    if (!MBB->empty() && MBB->back().getDesc().isReturn()) {
+    // Things marked both call and return are tail calls; do not do this for
+    // them.  The tail callee need not take the same registers as input
+    // that it produces as output, and there are dependencies for its input
+    // registers elsewhere.
+    if (!MBB->empty() && MBB->back().getDesc().isReturn()
+        && !MBB->back().getDesc().isCall()) {
       MachineInstr *Ret = &MBB->back();
 
       for (MachineRegisterInfo::liveout_iterator