This is possible:
authorEvan Cheng <evan.cheng@apple.com>
Tue, 26 Feb 2008 08:03:41 +0000 (08:03 +0000)
committerEvan Cheng <evan.cheng@apple.com>
Tue, 26 Feb 2008 08:03:41 +0000 (08:03 +0000)
commitc886c460e4fc305a1b79d1e7782584c7aa7aa91f
treed9131eeb7943a83dd5ca0889343fd2ad8e006b3c
parent0254e7033a1d879357e582dcdc1943e656192768
This is possible:
vr1 = extract_subreg vr2, 3
...
vr3 = extract_subreg vr1, 2
The end result is vr3 is equal to vr2 with subidx 2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47592 91177308-0d34-0410-b5e6-96231b3b80d8
lib/CodeGen/SimpleRegisterCoalescing.cpp
test/CodeGen/X86/2008-02-25-X86-64-CoalescerBug.ll [new file with mode: 0644]