Author: dim Date: Tue Dec 9 20:04:26 2014 New Revision: 275651 URL: https://svnweb.freebsd.org/changeset/base/275651
Log: Add llvm patch corresponding to r275633. Added: head/contrib/llvm/patches/patch-r275633-llvm-r223171-fix-vectorizer.diff Added: head/contrib/llvm/patches/patch-r275633-llvm-r223171-fix-vectorizer.diff ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/contrib/llvm/patches/patch-r275633-llvm-r223171-fix-vectorizer.diff Tue Dec 9 20:04:26 2014 (r275651) @@ -0,0 +1,71 @@ +Pull in r223171 from upstream llvm trunk (by Michael Zolotukhin): + + PR21302. Vectorize only bottom-tested loops. + + rdar://problem/18886083 + +This fixes a bug in the llvm vectorizer, which could sometimes cause +vectorized loops to perform an additional iteration, leading to possible +buffer overruns. Symptoms of this, which are usually segfaults, were +first noticed when building gcc ports, here: + +https://lists.freebsd.org/pipermail/freebsd-ports/2014-September/095466.html +https://lists.freebsd.org/pipermail/freebsd-toolchain/2014-September/001211.html + +Introduced here: http://svnweb.freebsd.org/changeset/base/275633 + +Index: lib/Transforms/Vectorize/LoopVectorize.cpp +=================================================================== +--- lib/Transforms/Vectorize/LoopVectorize.cpp (revision 21) ++++ lib/Transforms/Vectorize/LoopVectorize.cpp (revision 22) +@@ -2864,6 +2864,14 @@ bool LoopVectorizationLegality::canVectorize() { + if (!TheLoop->getExitingBlock()) + return false; + ++ // We only handle bottom-tested loops, i.e. loop in which the condition is ++ // checked at the end of each iteration. With that we can assume that all ++ // instructions in the loop are executed the same number of times. ++ if (TheLoop->getExitingBlock() != TheLoop->getLoopLatch()) { ++ DEBUG(dbgs() << "LV: loop control flow is not understood by vectorizer\n"); ++ return false; ++ } ++ + // We need to have a loop header. + DEBUG(dbgs() << "LV: Found a loop: " << + TheLoop->getHeader()->getName() << '\n'); +Index: test/Transforms/LoopVectorize/loop-form.ll +=================================================================== +--- test/Transforms/LoopVectorize/loop-form.ll (revision 0) ++++ test/Transforms/LoopVectorize/loop-form.ll (revision 22) +@@ -0,0 +1,31 @@ ++; RUN: opt -S -loop-vectorize < %s | FileCheck %s ++target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" ++ ++; Check that we vectorize only bottom-tested loops. ++; This is a reduced testcase from PR21302. ++; ++; rdar://problem/18886083 ++ ++%struct.X = type { i32, i16 } ++; CHECK-LABEL: @foo( ++; CHECK-NOT: vector.body ++ ++define void @foo(i32 %n) { ++entry: ++ br label %for.cond ++ ++for.cond: ++ %i = phi i32 [ 0, %entry ], [ %inc, %for.body ] ++ %cmp = icmp slt i32 %i, %n ++ br i1 %cmp, label %for.body, label %if.end ++ ++for.body: ++ %iprom = sext i32 %i to i64 ++ %b = getelementptr inbounds %struct.X* undef, i64 %iprom, i32 1 ++ store i16 0, i16* %b, align 4 ++ %inc = add nsw i32 %i, 1 ++ br label %for.cond ++ ++if.end: ++ ret void ++} _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
