https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116893
Bug ID: 116893
Summary: -fipa-cp-clone breaks mismatched-dealloc diagnostic
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ipa
Assignee: unassigned at gcc dot gnu.org
Reporter: a1ba.omarov at gmail dot com
Target Milestone: ---
Created attachment 59224
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59224&action=edit
-save-temps output from GCC 13.2
I've been adding `__attribute__((malloc(deallocator, ptr-index))))` to my
library. As it allows users to pass custom alloc/free function and malloc
attribute can only be applied to functions, I added simple wrappers and applied
this attribute to them.
However, when I turned `-O3`, it caused `-Wmismatched-dealloc` to trigger on
seemingly valid code. After checking each flag that turns on `-O3` level, I
figured out that it's caused by `-fipa-cp-clone`. My assumption is that GCC
performs cloning on the wrapper function, and it breaks alloc-free link set by
malloc attribute. Forcibly setting `__attribute__((noclone))` on the function
helps to avoid the issue.
Minimal reproducible example: https://godbolt.org/z/rnoGfKrY4
Locally I only have GCC 13.2 installed, therefore attached -save-temps output
is from 13.2, but on link above reported GCC version is
"(Compiler-Explorer-Build-gcc-74a0ff6c2c680b8b4554af80f55361af58e6fb1b-binutils-2.42)
15.0.0 20240929 (experimental)".
