https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65412
Bug ID: 65412
Summary: missing control flow optimisation
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: skvadrik at gmail dot com
Created attachment 35023
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35023&action=edit
files 1.c (source), 1.s (gcc assembly), 2.s (clang assembly)
Consider the following code:
void f(int x)
{
if (x == 0) f0();
else if (x == 1) f1();
else if (x == 2) f2();
else if (x == 3) f3();
else if (x == 4) f4();
else if (x == 5) f5();
}
gcc-4.9.2 doesn't optimize ifs to decision tree, jump table or something (see
1.s in attach). clang does (2.s in attach, jump table).
Maybe you could improve that?
