https://bugs.kde.org/show_bug.cgi?id=434193
Bug ID: 434193
Summary: GCC 9+ inlined strcmp causes "Conditional jump or move
depends on uninitialised value" report
Product: valgrind
Version: unspecified
Platform: Debian testing
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: memcheck
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 136531
--> https://bugs.kde.org/attachment.cgi?id=136531&action=edit
a.c
GCC 9.3.0 (OpenEmbedded, Ubuntu 20.04) and GCC 10.2.1 (Debian Bullseye) with
-O2 generate x86 and x86-64 code that causes memcheck (v2.16.1,
8b1961511c93962ea2a9b918af8e9c32e3c24d71) to report:
==4112219== Conditional jump or move depends on uninitialised value(s)
==4112219== at 0x10906D: main (a.c:10)
STEPS TO REPRODUCE
gcc -O3 a.c b.c
valgrind ./a.out
(the files need to be separate so that GCC can't see the implementation of the
fill function when compiling main.)
The generated code contains:
1067: 66 83 7c 24 0a 73 cmpw $0x73,0xa(%rsp)
106d: 75 e9 jne 1058 <main+0x18>
where the cmpw is comparing a 16-bit word against 's', '\0' when only '\0' was
written to that part of the buffer.
This appears to be similar to bug 413642 and bug 420780.
--
You are receiving this mail because:
You are watching all bug changes.
