https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98952
Bug ID: 98952
Summary: powerpc*: __trampoline_setup inverted test for
trampoline size
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libgcc
Assignee: unassigned at gcc dot gnu.org
Reporter: tuliom at ascii dot art.br
Target Milestone: ---
In tramp.S, we have the following:
/* R3 = stack address to store trampoline */
/* R4 = length of trampoline area */
/* R5 = function address */
/* R6 = static chain */
FUNC_START(__trampoline_setup)
...
li r8,trampoline_size /* verify that the trampoline is big
enough */
cmpw cr1,r8,r4
...
blt cr1,.Labort
It's aborting if r8 < r4.
However, I expected it to abort if r4 < r8, which means the allocated
trampoline area is not enough to fit the trampoline.
One could replace li + cmpw with just:
cmpwi cr1,r4,trampoline_size
I can't reproduce this issue on GCC because the allocated length (r4) is always
equals to the required length (r8).
However, this happens when mixing other compilers, e.g.
https://github.com/JuliaLang/julia/issues/32154#issuecomment-766536590
