http://llvm.org/bugs/show_bug.cgi?id=22703
Bug ID: 22703
Summary: Loop vectorizer seems very reluctant to make use of
PMULLD
Product: new-bugs
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: new bugs
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected]
Classification: Unclassified
Created attachment 13946
--> http://llvm.org/bugs/attachment.cgi?id=13946&action=edit
Sample code
I expected the attached code to produce PMULLD on x86-64 (or x86-32) with
SSE4.1 enabled.
Command line used:
clang++ -S -O3 -msse4.1 floop.cpp
Using this:
clang++ -S -O3 -msse4.1 -Rpass-analysis=loop-vectorize floop.cpp
Gives:
floop.cpp:8:5: remark: not beneficial to vectorize and user disabled
interleaving [-Rpass-analysis=loop-vectorize]
for (i=0;i<100;i++) a[i]= (float) (i*i);
Adding these:
#pragma clang loop vectorize(enable)
#pragma clang loop interleave(enable)
it unrolls the loop and uses pmuludq, but still no pmulld.
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
LLVMbugs mailing list
[email protected]
http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs
