[llvm-bugs] [Bug 43910] New: Loop splitting based on monotonic condition between indvar and trip count
via llvm-bugs
llvm-bugs at lists.llvm.org
Tue Nov 5 09:34:56 PST 2019
https://bugs.llvm.org/show_bug.cgi?id=43910
Bug ID: 43910
Summary: Loop splitting based on monotonic condition between
indvar and trip count
Product: libraries
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: Loop Optimizer
Assignee: unassignedbugs at nondot.org
Reporter: lebedev.ri at gmail.com
CC: llvm-bugs at lists.llvm.org
We could have something like:
void body();
void mainwork();
void remainder();
void bad(unsigned width) {
for(int col = 0; col < width; ++col) {
if(col >= (width - (width % 8))) // last 'width % 8' pixels.
remainder();
else
mainwork();
body();
}
}
Currently that loop is left as-is.
But it could be split into something like this, thus removing conditional from
loop.
void body();
void mainwork();
void remainder();
void good(unsigned width) {
for(int col = 0; col < (width - (width % 8)); ++col) {
if(false /*col >= (width - (width % 8))*/) // last 'width % 8' pixels.
remainder();
else
mainwork();
body();
}
for(int col = (width - (width % 8)); col < width; ++col) {
if(true /*col >= (width - (width % 8))*/) // last 'width % 8' pixels.
remainder();
else
mainwork();
body();
}
}
https://godbolt.org/z/SVWuJV
--
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20191105/cd3c720e/attachment.html>
More information about the llvm-bugs
mailing list