isNull() performance

[darkblueb]

during testing using callgrind , the function call costs of geos::geom::Envelope::isNull() indicate that performance may not be good. Due to the number of calls to this function, a closer look may be worthwhile.

BaseOS: Ubuntu Linux Compiler: gcc-8

---

#!/bin/bash

GEOS_SRC_BASE='/home/user/srcs_live105/geos_gitea'
LD_LIBRARY_PATH='/home/user/srcs_live105/geos_master_cmake/build/lib/'

## C hooks example
#gcc -c -o trace.o trace.c
# CXXFLAGS='-v -Og -ggdb3 -std=c++11 -DUSE_UNSTABLE_GEOS_CPP_API -D_GLIBCXX_PROFILE'

## Callgrind ready ; AVX instructions enabled
CXXFLAGS='-v -O3 -ggdb3 -std=c++11 -march=sandybridge -mtune=sandybridge  -DUSE_UNSTABLE_GEOS_CPP_API'

gcc ${CXXFLAGS} \
  -I${GEOS_SRC_BASE}/include  \
  -I/usr/include/c++/8 -I/usr/include/x86_64-linux-gnu/c++/8 \
  -L/home/user/srcs_live105/geos_master_cmake/build/lib/ \
  InteriorPtArea_app.cpp  \
  -o  app_intpt_O3 \
  -lm -lstdc++ -lpthread  -l:libgeos.so.3.8.0dev

[pramsey]

I ran Instruments.app against a Release build and I'm not seeing heavy use of isNull(). The heaviest stack ends on SegmentNode::compareTo()