5 # This script helps find the optimization difference between two llvm
6 # builds. It is useful when you have a build that is known to work and
7 # one that exhibits an optimization problem. Identifying the difference
8 # between the two builds can lead to discovery of the source of a
11 # The script takes two llvm build paths as arguments. These specify the
12 # the two llvm builds to compare. It is generally expected that they
13 # are "close cousins". That is, they are the same except that the
14 # second build contains some experimental optimization features that
15 # are suspected of producing a misoptimization.
17 # The script takes two bytecode files, one from each build. They are
18 # presumed to be a compilation of the same program or program fragment
19 # with the only difference being the builds.
21 # The script operates by iteratively applying the optimizations that gccas
22 # and gccld run until there is a difference in the assembly resulting
23 # from the optimization. The difference is then reported with the set of
24 # optimization passes that produce the difference.
26 # To work around differences in the assembly language format, the script
27 # can also take two filter arguments that post-process the assembly
28 # so they can be differenced without making false positives for known
29 # differences in the two builds. These filters are optional.
32 # findoptdiff llvm1 llvm2 bc1 bc2 filter1 filter2
36 # is the path to the first llvm build dir
38 # is the path to the second llvm build dir
40 # is the bytecode file for the first llvm environment
42 # is the bytecode file for the second llvm environment
44 # is an optional filter for filtering the llvm1 generated assembly
46 # is an optional filter for filtering the llvm2 generated assembly
53 if [ -z "$filt1" ] ; then
57 if [ -z "$filt2" ] ; then
64 dir1="/proj/llvm/llvm-test-1/External/SPEC/CINT2000/300.twolf"
65 opt1="/proj/llvm/llvm-1/Debug/bin/opt"
66 dis1="/proj/llvm/llvm-1/Debug/bin/llvm-dis"
67 dir2="/proj/llvm/llvm-test-2/External/SPEC/CINT2000/300.twolf"
68 opt2="/proj/llvm/llvm-2/Debug/bin/opt"
69 dis2="/proj/llvm/llvm-2/Debug/bin/llvm-dis"
70 bcfile="Output/300.twolf.linked.rbc"
73 all_switches="-verify -lowersetjmp -funcresolve -raiseallocs -simplifycfg -mem2reg -globalopt -globaldce -ipconstprop -deadargelim -instcombine -simplifycfg -prune-eh -inline -simplify-libcalls -argpromotion -raise -tailduplicate -simplifycfg -scalarrepl -instcombine -predsimplify -condprop -tailcallelim -simplifycfg -reassociate -licm -loop-unswitch -instcombine -indvars -loop-unroll -instcombine -load-vn -gcse -sccp -instcombine -condprop -dse -dce -simplifycfg -deadtypeelim -constmerge -funcresolve -internalize -ipsccp -globalopt -constmerge -deadargelim -inline -prune-eh -globalopt -globaldce -argpromotion -instcombine -predsimplify -scalarrepl -globalsmodref-aa -licm -load-vn -gcse -dse -instcombine -simplifycfg -verify"
78 $opt1 $switches_to_use "$bcfile" -o - | $dis1 | $filt1 > "$optll"
80 $opt2 $switches_to_use "$bcfile" -o - | $dis2 | $filt2 > "$optll"
81 diff "$dir1/$optll" "$dir2/$optll" > /dev/null
82 if [ $? -ne 0 ] ; then
84 echo "Diff fails with these switches:"
87 diff "$dir1/$optll" "$dir2/$optll" | head
93 for sw in $all_switches ; do
95 switches="$switches $sw"
96 if tryit "$switches" ; then