[gcc] Remove few changes from machine-independent part.

[gcc] Remove few changes from machine-independent part.

This change restores explow.c and reload.c back to their original state.

This change can affect the performance, as it may limit the number of cases when lea instruction is generated.
However, the change is the "right thing" to do. Lea problems, if any, should be solved in i386-specific code.

[pasko-google - do not use, 2010-07-27 21:54:52]

LGTM

Generally, this is the right thing to do. Though in practice performance
implications are scary to me. Please, test this with the perf testing buildbot
that we are going to get :)

http://codereview.chromium.org/2825071/diff/1/4
File gcc/gcc/reload.c (left):

http://codereview.chromium.org/2825071/diff/1/4#oldcode4696
gcc/gcc/reload.c:4696: reg_equiv_constant[regno]
I didn't change this code. Changing something in the core of reload.c is indeed
hardcore.

[eaeltsin, 2010-07-29 08:53:21]

I'll submit this. If performance degrades, I'll investigate ASAP.

http://codereview.chromium.org/2825071/diff/1/4
File gcc/gcc/reload.c (left):

http://codereview.chromium.org/2825071/diff/1/4#oldcode4696
gcc/gcc/reload.c:4696: reg_equiv_constant[regno]
On 2010/07/27 21:54:52, pasko wrote:
> I didn't change this code. Changing something in the core of reload.c is
indeed
> hardcore.

This code was different from the original. I'm not saying you did this - in fact
it doesn't matter who did this :-)