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authorTom Stellard <thomas.stellard@amd.com>2014-04-09 00:20:38 +0000
committerTom Stellard <thomas.stellard@amd.com>2014-04-09 00:20:38 +0000
commitb1fb1964fdbc57cf1a9c8b1d8794476d8d041681 (patch)
tree442599d518f51a9acbd7b320dd3c7d3b81466c64 /lib/Transforms/Vectorize/LoopVectorize.cpp
parent29f0c4eafa67b97be70116306642fb75b144be41 (diff)
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Merging r199570:
------------------------------------------------------------------------ r199570 | aschwaighofer | 2014-01-18 22:18:31 -0500 (Sat, 18 Jan 2014) | 11 lines LoopVectorizer: A reduction that has multiple uses of the reduction value is not a reduction. Really. Under certain circumstances (the use list of an instruction has to be set up right - hence the extra pass in the test case) we would not recognize when a value in a potential reduction cycle was used multiple times by the reduction cycle. Fixes PR18526. radar://15851149 ------------------------------------------------------------------------ git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_34@205818 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Vectorize/LoopVectorize.cpp')
-rw-r--r--lib/Transforms/Vectorize/LoopVectorize.cpp13
1 files changed, 11 insertions, 2 deletions
diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 5e758713ed..f9f6b18940 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -4191,13 +4191,22 @@ bool LoopVectorizationLegality::AddReductionVar(PHINode *Phi,
continue;
}
- // Process instructions only once (termination).
+ // Process instructions only once (termination). Each reduction cycle
+ // value must only be used once, except by phi nodes and min/max
+ // reductions which are represented as a cmp followed by a select.
+ ReductionInstDesc IgnoredVal(false, 0);
if (VisitedInsts.insert(Usr)) {
if (isa<PHINode>(Usr))
PHIs.push_back(Usr);
else
NonPHIs.push_back(Usr);
- }
+ } else if (!isa<PHINode>(Usr) &&
+ ((!isa<FCmpInst>(Usr) &&
+ !isa<ICmpInst>(Usr) &&
+ !isa<SelectInst>(Usr)) ||
+ !isMinMaxSelectCmpPattern(Usr, IgnoredVal).IsReduction))
+ return false;
+
// Remember that we completed the cycle.
if (Usr == Phi)
FoundStartPHI = true;