https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101912
Bug ID: 101912
Summary: -Wmaybe-uninitialized false alarm in tzdb localtime.c
Product: gcc
Version: 11.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: eggert at cs dot ucla.edu
Target Milestone: ---
Created attachment 51303
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51303&action=edit
-Wuninitialized false alarm
This is a simplified version of a problem I found while compiling tzdb's
localtime.c with gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-1) on x86-64.
Compile the attached program w.i with:
gcc -Wmaybe-uninitialized -O2 -S w.i
The output is:
w.i: In function ‘tzloadbody’:
w.i:17:27: warning: ‘prevcorr’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
16 | : (corr == prevcorr
| ~~~~~~~~~~~~~~~~~
17 | || corr == prevcorr - 1)))))
| ^~~~~~~~~~~~~~~~~~~~~~~~
This is a false alarm, since the underlined code is executed only when leapcnt
is nonzero, and leapcnt is set to a nonzero value only after prevcorr is
initialized.
