From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Sat, 4 Feb 2012 05:41:20 +0000 (+0000)
Subject: Correctly terminate a physreg redefined by an early clobber.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=7e899cbb9127c02c58f6e774186a533b0d00681d;p=oota-llvm.git

Correctly terminate a physreg redefined by an early clobber.

I don't have a test that fails because of this, but a test case like
CodeGen/X86/2009-12-01-EarlyClobberBug.ll exposes the problem.  EAX is
redefined by a tied early clobber operand on inline asm, and the live
range should look like this:

  %EAX,inf = [48r,64e:0)[64e,80r:1)  0@48r 1@64e

Previously, the two values got merged:

  %EAX,inf = [48r,80r:0)  0@48r

With this bug fixed, the REDEF_BY_EC VNInfo flag is no longer needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149768 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index e268819897c..d72009ccd22 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -402,7 +402,7 @@ void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock *MBB,
       if (DefIdx != -1) {
         if (mi->isRegTiedToUseOperand(DefIdx)) {
           // Two-address instruction.
-          end = baseIndex.getRegSlot();
+          end = baseIndex.getRegSlot(mi->getOperand(DefIdx).isEarlyClobber());
         } else {
           // Another instruction redefines the register before it is ever read.
           // Then the register is essentially dead at the instruction that