https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86952
Bug ID: 86952
Summary: Avoid jump table for switch statement with
-mindirect-branch=thunk
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
CC: wei3.xiao at intel dot com
Blocks: 84072
Target Milestone: ---
Target: i386,x86-64
Why is GCC generating a jump table for a five-entry switch statement if
retpolines are on? This has got to be a *huge* performance loss. The
retpoline sequence is very, very slow, and branches aren't that slow.
A five-entry switch is only three branches deep.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84072
[Bug 84072] [meta-bug] -mindirect-branch=thunk issues
