https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #16 from Ajit Kumar Agarwal ---
This patch https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624751.html
removes the zero extension from the below testcase that has different cfg, My
patch is not based on any CFG shape but it is g
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #15 from Surya Kumari Jangala ---
This is another test which has unnecessary zero extension:
#include
bool glob1;
bool glob2;
bool foo (int a, bool d)
{
bool c;
if (a > 2)
c = glob1 & glob2;
else
c = glob1 | glob2;
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
Ajit Kumar Agarwal changed:
What|Removed |Added
Ever confirmed|0 |1
Last reconfirmed|
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #14 from Richard Biener ---
I get, for -mcpu=power9 or power10
foo:
.LFB0:
.cfi_startproc
cmpwi 0,3,2
bgt 0,.L3
cmpwi 0,4,9
li 3,1
isel 3,0,3,1
blr
.p2align 4,,15
.L3:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #13 from Surya Kumari Jangala ---
Thanks David and Segher for your comments. I wanted to note down my analysis
and thoughts from when I had worked on this bug in January. Ajit is looking
into it now.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #12 from Segher Boessenkool ---
What David says :-)
We really could use something good for this, it has been a problem for all
GCC targets since forever; it hurts rs6000 more than most though.
Before RA this is a diamond, one side
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #11 from David Edelsohn ---
Have you looked on the GCC mailing list for zero-extend elimination (zee) and
sign-extend elimination (see)? The many, previous proposals for such passes.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #10 from Surya Kumari Jangala ---
After the expand pass, we have a single return bb which first zero extends r117
(this reg holds the return value which has been set by predecessor blocks).
Zero extension is done because r117 is of m
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #9 from Surya Kumari Jangala ---
The same issue of unnecessary rldicl instruction is there if we change return
value from bool to int.
int foo (int a, int b)
{
if (a > 2)
return 0;
if (b < 10)
return 1;
return 0;
}
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #8 from Surya Kumari Jangala ---
Using -O3 with gcc13, I got (with the test in comment 2):
For P8:
cmpwi 0,3,2
bgt 0,.L3
subfic 4,4,9
srdi 3,4,63
xori 3,3,0x1
rldicl 3,3,0,63
b
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #7 from Segher Boessenkool ---
I do get that exact same code with everything from GCC 6 to GCC 12 as well
though (modulo a small regression in GCC 10).
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #6 from Segher Boessenkool ---
Ugh, this PR is for GCC 12 only, ignore me please :-)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #5 from Segher Boessenkool ---
I get simply
subfic 3,3,2
srdi 3,3,63
xori 3,3,0x1
blr
for this code. Did you use -O0 or similar?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #4 from HaoChen Gui ---
output with "-fdump-tree-optimized=/dev/stdout"
;; Function foo (foo, funcdef_no=0, decl_uid=3317, cgraph_uid=1,
symbol_order=0)
Removing basic block 5
_Bool foo (int a, int b)
{
_Bool _1;
_Bool _5;
[
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #3 from Andrew Pinski ---
I wonder if this is because on the gimple level we are producing:
_5 = b_3(D) <= 9;
_6 = a_2(D) <= 2;
_7 = _5 & _6;
Now.
Can you add -fdump-tree-optimized=/dev/stdout and provide the output of that
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
--- Comment #2 from HaoChen Gui ---
Sorry, I pasted wrong codes. Here are the correct ones.
//test.c
#include
bool foo (int a, int b)
{
if (a > 2)
return false;
if (b < 10)
return true;
return false;
}
//assembly with the trunk
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103784
Andrew Pinski changed:
What|Removed |Added
Keywords||missed-optimization
--- Comment #1 from
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