https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120468
Bug ID: 120468
Summary: Inlining fails when using -momit-leaf-frame-pointer,
optimize attribute, and push_options pragma
Product: gcc
Version: 14.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ipa
Assignee: unassigned at gcc dot gnu.org
Reporter: abbeyj+gcc at gmail dot com
Target Milestone: ---
In the source code below, I would expect the call to `foo` to be inlined into
`baz`, but it isn't. Compile with `g++ -O2 -fno-omit-frame-pointer
-momit-leaf-frame-pointer -c repro.cpp`
```
double g_d;
inline double& foo() { return g_d; }
__attribute__((optimize("-fno-unsafe-math-optimizations")))
void bar() {
}
#pragma GCC push_options
#pragma GCC pop_options
void baz() {
foo() = 1.0;
}
```
Removing the `optimize attribute or the pair of `pragma`s (or both) leads to
the inlining again happening as expected.
Compiling with `-fdump-ipa-inline` produces the following interesting
information:
```
...
target_flags (0x58002803/0x58202803)
...
IPA function summary for void baz()/3 inlinable
...
calls:
double& foo()/1 target specific option mismatch
freq:1.00 loop depth: 0 size: 2 time: 11 callee size: 1 stack: 0
...
```
The target_flags values above differ by 0x00200000. I believe that is
MASK_OMIT_LEAF_FRAME_POINTER. It looks like the flag for
`-momit-leaf-frame-pointer` has been changed between `foo` and `baz` so now
inlining can no longer happen.
Godbolt link: https://godbolt.org/z/aqq7j4bbr
This works in GCC v14.1 but fails in GCC v14.2 and later.
