Bug 1211845

Summary:	gcc does not report the warning -Wmaybe-uninitialized
Product:	[openSUSE] openSUSE Tumbleweed	Reporter:	Christopher Yeleighton <giecrilj>
Component:	Development	Assignee:	E-mail List <screening-team-bugs>
Status:	RESOLVED UPSTREAM	QA Contact:	E-mail List <qa-bugs>
Severity:	Normal
Priority:	P5 - None
Version:	Current
Target Milestone:	---
Hardware:	x86-64
OS:	openSUSE Tumbleweed
URL:	https://gcc.gnu.org/wiki/Better_Uninitialized_Warnings#problem_ccp
See Also:	https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18501
Whiteboard:
Found By:	Community User	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description Christopher Yeleighton 2023-05-31 07:51:05 UTC

# The following script fails for me:
! echo >foo.c 'void *foo (int q)  { void *r; if (q) r = 0; return r; }' ||
! gcc -c -O -Wall -Werror foo.c
# There should be a warning [-Wmaybe-uninitialized].

Comment 1 Christopher Yeleighton 2023-05-31 08:24:20 UTC

CCP (Conditional Constant Propagation) assumes any value for an uninitialized variable, effectively removing uninitialized uses before the second phase can detect them.