https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63637
Bug ID: 63637
Summary: CSE() on x86 asm()-s no longer working due to PR/60663
fix
Product: gcc
Version: 4.9.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: jbeulich at novell dot com
Created attachment 33800
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33800&action=edit
example
The attached example, derived after seeing x86 Linux'es this_cpu_read_stable()
no longer getting CSE'd as expected, demonstrates the issue. 4.8.3 folded all
four read_p() invocations and each pair of read_m().
Jakub pointed out that this is an effect of the fix for PR/60663 in connection
with all x86 asm()-s getting two clobbers attached.
