https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109147
Bug ID: 109147
Summary: Missing IPA-VRP for return values
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: testsuite
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
CC: david.spickett at linaro dot org, unassigned at gcc dot
gnu.org
Depends on: 109146
Target Milestone: ---
+++ This bug was initially created as a clone of Bug #109146 +++
I guess we should turn this primarily into an enhancement request to optimize
this.
I believe that is a request for return value ranges in IPA-VRP.
So a testcase could be:
__attribute__((noinline)) static int
foo (int a, int b)
{
return a == b;
}
int
bar (int a, int b)
{
return foo (a, b) != 0;
}
__attribute__((noinline)) static int
baz (int a)
{
if (a > 10 || a < -10)
return 0;
return a;
}
int
qux (int a)
{
return baz (a) == 42;
}
where if we determine that foo always returns [0, 1] and baz [-10, 10], then we
can
optimize that return ret != 0; into return ret; and ret == 42 into 0.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109146
[Bug 109146] Tail call prevention in frame-address.c is not correct
