How to replace -O1 with corresponding -f's?

[Andrew Haley]

Sergei Organov writes:
 > Hi,
 > 
 > Using gcc compiled from gcc-4_0-branch, in an attempt to see which
 > particular optimization option makes my test case to be mis-optimized, I
 > try to replace -O1 (which toggles on the problem) with corresponding set
 > of -fxxx optimization options.

In general you can't do this.  You can turn some optimization passes
off, though.

 > How one finds out what optimization pass misbehaves?

Look at the dumps.  If you use the gcc option -da you'll get a full
set of RTL dump files.

Andrew.