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[Bug rtl-optimization/63637] New: CSE() on x86 asm()-s no longer working due to PR/60663 fix
- From: "jbeulich at novell dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 24 Oct 2014 11:33:03 +0000
- Subject: [Bug rtl-optimization/63637] New: CSE() on x86 asm()-s no longer working due to PR/60663 fix
- Auto-submitted: auto-generated
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.