https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87173
Bug ID: 87173
Summary: -Walloc-size-larger-than= silently fails for
operands/size values larger than __SIZE_MAX__
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: jozef.l at mittosystems dot com
Target Milestone: ---
Created attachment 44640
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44640&action=edit
testcase.c
Exposed by gcc.dg/Walloc-size-larger-than-{4,5,6,7}.c for msp430-elf, on
latest trunk.
- If the operand to the allocation function being checked is larger than
__SIZE_MAX__, no warning is emitted.
- If the value passed to -Walloc-size-larger-than= is larger than or equal to
__SIZE_MAX__, no warning is emitted.
e.g. for msp430-elf, where __SIZE_MAX__ is 65535. testcase.c attached.
> msp430-elf-gcc -O -ftrack-macro-expansion=0 -Walloc-size-larger-than=65534
> testcase.c -S
> testcase.c: In function 'f':
> testcase.c:6:3: warning: argument 1 value '65535' exceeds maximum object size
> 65534 [-Walloc-size-larger-than=]
> 6 | T (__builtin_malloc (a));
> | ^
> testcase.c:6:3: note: in a call to built-in allocation function
> '__builtin_malloc'
The expected warning for 65536 (__SIZE_MAX__ + 1) exceeding maximum object size
is missing.
Again, with __SIZE_MAX__ as the parameter to -Walloc-size-larger-than=
> msp430-elf-gcc -O -ftrack-macro-expansion=0 -Walloc-size-larger-than=65535
> testcase.c -S
No warnings output.
