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[Bug tree-optimization/62012] New: Loop is not vectorized after function inlining (SCEV)
- From: "ysrumyan at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 04 Aug 2014 14:48:48 +0000
- Subject: [Bug tree-optimization/62012] New: Loop is not vectorized after function inlining (SCEV)
- Auto-submitted: auto-generated
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62012
Bug ID: 62012
Summary: Loop is not vectorized after function inlining (SCEV)
Product: gcc
Version: 4.10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ysrumyan at gmail dot com
We noticed that for one important benchmark using '-lto' options leads to
performance degradation which is caused by not-vectorizing the hottest loop
after function inlining. I can able to reproduce this deficiency using simple
test-case:
if we passed class by reference to function (it need to be compiled with
-DPARAM macros) loop is vectorized:
g++ -Ofast -m64 -march=core-avx2 -c test.cpp -fdump-tree-vect-details -fopenmp
-DPARAM; grep 'note: vectorized' test.cpp.114t.vect
test.cpp:45:1: note: vectorized 1 loops in function.
But if we compile it without macros we get:
g++ -Ofast -m64 -march=core-avx2 -c test.cpp -fdump-tree-vect-details
-fopenmp; grep 'note: vectorized' test.cpp.114t.vect
test.cpp:45:1: note: vectorized 0 loops in function.
It looks like SCEV issue.