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Diffstat (limited to 'contrib/llvm/utils/findoptdiff')
| -rwxr-xr-x | contrib/llvm/utils/findoptdiff | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/contrib/llvm/utils/findoptdiff b/contrib/llvm/utils/findoptdiff new file mode 100755 index 0000000..4f8d08d --- /dev/null +++ b/contrib/llvm/utils/findoptdiff @@ -0,0 +1,101 @@ +#!/bin/bash +# +# findoptdiff +# +# This script helps find the optimization difference between two llvm +# builds. It is useful when you have a build that is known to work and +# one that exhibits an optimization problem. Identifying the difference +# between the two builds can lead to discovery of the source of a +# mis-optimization. +# +# The script takes two llvm build paths as arguments. These specify the +# the two llvm builds to compare. It is generally expected that they +# are "close cousins". That is, they are the same except that the +# second build contains some experimental optimization features that +# are suspected of producing a misoptimization. +# +# The script takes two bytecode files, one from each build. They are +# presumed to be a compilation of the same program or program fragment +# with the only difference being the builds. +# +# The script operates by iteratively applying the optimizations that gccas +# and gccld run until there is a difference in the assembly resulting +# from the optimization. The difference is then reported with the set of +# optimization passes that produce the difference. The processing +# continues until all optimization passes have been tried. The differences +# for each pass, if they do differ, are placed in a diffs.# file. +# +# To work around differences in the assembly language format, the script +# can also take two filter arguments that post-process the assembly +# so they can be differenced without making false positives for known +# differences in the two builds. These filters are optional. +# +# Usage: +# findoptdiff llvm1 llvm2 bc1 bc2 filter1 filter2 +# +# Where: +# llvm1 +# is the path to the first llvm build dir +# llvm2 +# is the path to the second llvm build dir +# bc1 +# is the bytecode file for the first llvm environment +# bc2 +# is the bytecode file for the second llvm environment +# filter1 +# is an optional filter for filtering the llvm1 generated assembly +# filter2 +# is an optional filter for filtering the llvm2 generated assembly +# +llvm1=$1 +llvm2=$2 +bc1=$3 +bc2=$4 +filt1=$5 +filt2=$6 +if [ -z "$filt1" ] ; then + filt1="cat" +fi +if [ -z "$filt2" ] ; then + filt2="cat" +fi +opt1="${bc1}.opt" +opt2="${bc2}.opt" +ll1="${bc1}.ll" +ll2="${bc2}.ll" +opt1ll="${bc1}.opt.ll" +opt2ll="${bc2}.opt.ll" +dis1="$llvm1/Debug/bin/llvm-dis" +dis2="$llvm2/Debug/bin/llvm-dis" +opt1="$llvm1/Debug/bin/opt" +opt2="$llvm2/Debug/bin/opt" + +all_switches="-verify -lowersetjmp -simplifycfg -mem2reg -globalopt -globaldce -ipconstprop -deadargelim -instcombine -simplifycfg -prune-eh -inline -simplify-libcalls -argpromotion -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 -internalize -ipsccp -globalopt -constmerge -deadargelim -inline -prune-eh -globalopt -globaldce -argpromotion -instcombine -predsimplify -scalarrepl -globalsmodref-aa -licm -load-vn -gcse -dse -instcombine -simplifycfg -verify" + +#counter=0 +function tryit { + switches_to_use="$1" + $opt1 $switches_to_use "$bc1" -o - | $dis1 | $filt1 > "$opt1ll" + $opt2 $switches_to_use "$bc2" -o - | $dis2 | $filt2 > "$opt2ll" + diffs="diffs."$((counter++)) + diff "$opt1ll" "$opt2ll" > $diffs + if [ $? -ne 0 ] ; then + echo + echo "Diff fails with these switches:" + echo $switches + echo "Differences:" + head $diffs + echo 'Switches:' $switches_to_use >> $diffs + else + rm $diffs + fi + return 1 +} + +for sw in $all_switches ; do + echo -n " $sw" + switches="$switches $sw" + if tryit "$switches" ; then + break; + fi +done |
