Implement first D-specific optimization pass: -simplify-drtcalls. It uses the machinery of the standard -simplify-libcalls pass, but optimizes calls to the D runtime instead of calls to C libraries. At the moment, these optimizations are implemented by this pass: - Avoid the runtime call for `arr.length = newlen` if it can determine that the new length isn't longer than the old one. - Ditto for `cast(T[]) arr` if it will clearly always succeed. (e.g. if the length of the original array is zero, or if the old element size is a multiple of the new element size)

#!/bin/bash

HOST_TARGET=$1

[ "$HOST_TARGET" = "" ] && exit 1

REST=`echo $HOST_TARGET   | sed -e 's/[a-zA-Z0-9_]*\(\-.*\)/\1/'`
X86=`echo $HOST_TARGET    | sed -e 's/\(i[3-9]86\)\-.*/\1/'`
X86_64=`echo $HOST_TARGET | sed -e 's/\(x86_64\)\-.*/\1/'`

ALT=
if [ "$X86_64" != "$HOST_TARGET" ]; then
    ALT="i686$REST"

elif [ "$X86" != "$HOST_TARGET" ]; then
    ALT="x86_64$REST"
fi

echo $ALT