Physregs may hold multiple stack slot values at the same time.  Keep track of this, and use it to our advantage (bwahahah).  This allows us to eliminate another 60 instructions from smg2000 on PPC (probably significantly more on X86).  A common old-new diff looks like this:
Physregs may hold multiple stack slot values at the same time.  Keep track
of this, and use it to our advantage (bwahahah).  This allows us to eliminate another
60 instructions from smg2000 on PPC (probably significantly more on X86).  A common
old-new diff looks like this:

        stw r2, 3304(r1)
-       lwz r2, 3192(r1)
        stw r2, 3300(r1)
-       lwz r2, 3192(r1)
        stw r2, 3296(r1)
-       lwz r2, 3192(r1)
        stw r2, 3200(r1)
-       lwz r2, 3192(r1)
        stw r2, 3196(r1)
-       lwz r2, 3192(r1)
+       or r2, r2, r2
        stw r2, 3188(r1)

and

-       lwz r31, 604(r1)
-       lwz r13, 604(r1)
-       lwz r14, 604(r1)
-       lwz r15, 604(r1)
-       lwz r16, 604(r1)
-       lwz r30, 604(r1)
+       or r31, r30, r30
+       or r13, r30, r30
+       or r14, r30, r30
+       or r15, r30, r30
+       or r16, r30, r30
+       or r30, r30, r30

Removal of the R = R copies is coming next...


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@25919 91177308-0d34-0410-b5e6-96231b3b80d8

chubbymaggie/asap,GPUOpen-Drivers/llvm,dslab-epfl/asap,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,dslab-epfl/asap,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,chubbymaggie/asap,GPUOpen-Drivers/llvm,chubbymaggie/asap,llvm-mirror/llvm,apple/swift-llvm,dslab-epfl/asap,apple/swift-llvm,apple/swift-llvm,dslab-epfl/asap,chubbymaggie/asap,apple/swift-llvm,dslab-epfl/asap,apple/swift-llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,chubbymaggie/asap,dslab-epfl/asap,chubbymaggie/asap