We should remove the live range from the destination register only if *all* defs

are dead, not just the def of this register. I.e., a register could be dead, but
it's subreg isn't.

Testcase to follow with a subsequent patch.

llvm-svn: 106878

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp b/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 62096714178..5a30ddf5645 100644
--- a/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -1892,8 +1892,8 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) {
         if (li_->hasInterval(SrcReg)) {
           LiveInterval &RegInt = li_->getInterval(SrcReg);
           // If def of this move instruction is dead, remove its live range
-          // from the dstination register's live interval.
-          if (MI->registerDefIsDead(DstReg)) {
+          // from the destination register's live interval.
+          if (MI->allDefsAreDead()) {
             if (!ShortenDeadCopySrcLiveRange(RegInt, MI))
               ShortenDeadCopyLiveRange(RegInt, MI);
           } else {