[llvm] r222677 - [AArch64] Fix clobber computation in A57LoadBalancing pass.

[Chad Rosier]

Author: mcrosier
Date: Mon Nov 24 12:57:58 2014
New Revision: 222677

URL: http://llvm.org/viewvc/llvm-project?rev=222677&view=rev
Log:
[AArch64] Fix clobber computation in A57LoadBalancing pass.

Extremely difficult to reproduce, so no test case included.
PR21637

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp

Modified: llvm/trunk/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp?rev=222677&r1=222676&r2=222677&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64A57FPLoadBalancing.cpp Mon Nov 24 12:57:58 2014
@@ -481,10 +481,16 @@ int AArch64A57FPLoadBalancing::scavengeR
     RS.forward(I);
     AvailableRegs &= RS.getRegsAvailable(TRI->getRegClass(RegClassID));
 
-    // Remove any registers clobbered by a regmask.
+    // Remove any registers clobbered by a regmask or any def register that is
+    // immediately dead.
     for (auto J : I->operands()) {
       if (J.isRegMask())
         AvailableRegs.clearBitsNotInMask(J.getRegMask());
+
+      if (J.isReg() && J.isDef() && AvailableRegs[J.getReg()]) {
+        assert(J.isDead() && "Non-dead def should have been removed by now!");
+        AvailableRegs.reset(J.getReg());
+      }
     }
   }