https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92342
Bug ID: 92342
Summary: [10 Regression] a small missed transformation into
x?b:0
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Target: aarch64-linux-gnu
Take these two functions:
int f(int a,int b, int c)
{
return a==c?b:0;
}
int g(int a, int b, int c)
{
return b & -(a==c);
}
---- CUT ----
We used to produce the same code generation for both of them:
cmp w0, w2
csel w0, w1, wzr, eq
ret
But in GCC 10 we produce for g:
cmp w0, w2
csetm w0, eq
and w0, w0, w1
ret
I think this was introduced by:
2019-05-09 Segher Boessenkool <[email protected]>
* combine.c (combine_simplify_rtx): Don't make IF_THEN_ELSE RTL.
