[llvm-commits] [llvm] r166787 - in /llvm/trunk: lib/Transforms/Utils/LCSSA.cpp lib/Transforms/Utils/LoopSimplify.cpp test/Transforms/IndVarSimplify/verify-scev.ll
Benjamin Kramer
benny.kra at googlemail.com
Fri Oct 26 10:31:43 PDT 2012
Author: d0k
Date: Fri Oct 26 12:31:43 2012
New Revision: 166787
URL: http://llvm.org/viewvc/llvm-project?rev=166787&view=rev
Log:
Fix SCEV cache invalidation in LCSSA and LoopSimplify.
The LoopSimplify bug is pretty harmless because the loop goes from unanalyzable
to analyzable but the LCSSA bug is very nasty. It only comes into play with a
specific order of the LoopPassManager worklist and can cause actual
miscompilations, when a SCEV refers to a value that has been replaced with PHI
node. SCEVExpander may then insert code into the wrong place, either violating
domination or randomly miscompiling stuff.
Comes with an extensive test case reduced from the test-suite with
bugpoint+SCEVValidator.
Added:
llvm/trunk/test/Transforms/IndVarSimplify/verify-scev.ll
Modified:
llvm/trunk/lib/Transforms/Utils/LCSSA.cpp
llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
Modified: llvm/trunk/lib/Transforms/Utils/LCSSA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LCSSA.cpp?rev=166787&r1=166786&r2=166787&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LCSSA.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LCSSA.cpp Fri Oct 26 12:31:43 2012
@@ -53,6 +53,8 @@
// Cached analysis information for the current function.
DominatorTree *DT;
+ LoopInfo *LI;
+ ScalarEvolution *SE;
std::vector<BasicBlock*> LoopBlocks;
PredIteratorCache PredCache;
Loop *L;
@@ -117,6 +119,8 @@
L = TheLoop;
DT = &getAnalysis<DominatorTree>();
+ LI = &getAnalysis<LoopInfo>();
+ SE = getAnalysisIfAvailable<ScalarEvolution>();
// Get the set of exiting blocks.
SmallVector<BasicBlock*, 8> ExitBlocks;
@@ -244,6 +248,12 @@
// Remember that this phi makes the value alive in this block.
SSAUpdate.AddAvailableValue(ExitBB, PN);
+
+ // If the exiting block is part of a loop inserting a PHI may change its
+ // SCEV analysis. Conservatively drop any caches from it.
+ if (SE)
+ if (Loop *L = LI->getLoopFor(ExitBB))
+ SE->forgetLoop(L);
}
// Rewrite all uses outside the loop in terms of the new PHIs we just
@@ -258,6 +268,10 @@
if (PHINode *PN = dyn_cast<PHINode>(User))
UserBB = PN->getIncomingBlock(*UsesToRewrite[i]);
+ // Tell SCEV to reanalyze the value that's about to change.
+ if (SE)
+ SE->forgetValue(*UsesToRewrite[i]);
+
if (isa<PHINode>(UserBB->begin()) &&
isExitBlock(UserBB, ExitBlocks)) {
UsesToRewrite[i]->set(UserBB->begin());
Modified: llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp?rev=166787&r1=166786&r2=166787&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp Fri Oct 26 12:31:43 2012
@@ -194,6 +194,11 @@
BI->setCondition(ConstantInt::get(Cond->getType(),
!L->contains(BI->getSuccessor(0))));
+
+ // This may make the loop analyzable, force SCEV recomputation.
+ if (SE)
+ SE->forgetLoop(L);
+
Changed = true;
}
}
Added: llvm/trunk/test/Transforms/IndVarSimplify/verify-scev.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/verify-scev.ll?rev=166787&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/verify-scev.ll (added)
+++ llvm/trunk/test/Transforms/IndVarSimplify/verify-scev.ll Fri Oct 26 12:31:43 2012
@@ -0,0 +1,421 @@
+; RUN: opt < %s -S -indvars -verify-scev
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+
+define void @test1() nounwind uwtable ssp {
+entry:
+ br i1 undef, label %for.end, label %for.body
+
+for.body: ; preds = %for.body, %entry
+ br i1 false, label %for.end, label %for.body
+
+for.end: ; preds = %for.body, %entry
+ br i1 undef, label %for.end11, label %for.body3
+
+for.body3: ; preds = %for.end
+ unreachable
+
+for.end11: ; preds = %for.end
+ br i1 undef, label %while.body, label %while.end
+
+while.body: ; preds = %for.end11
+ unreachable
+
+while.end: ; preds = %for.end11
+ br i1 undef, label %if.end115, label %for.cond109
+
+for.cond109: ; preds = %while.end
+ unreachable
+
+if.end115: ; preds = %while.end
+ br i1 undef, label %while.body119.lr.ph.lr.ph, label %for.cond612
+
+while.body119.lr.ph.lr.ph: ; preds = %if.end115
+ br i1 undef, label %for.cond612, label %if.end123.us
+
+if.end123.us: ; preds = %while.body119.lr.ph.lr.ph
+ br label %for.cond132.us
+
+for.cond132.us: ; preds = %for.cond132.us, %if.end123.us
+ br i1 undef, label %if.then136.us, label %for.cond132.us
+
+if.then136.us: ; preds = %for.cond132.us
+ br i1 undef, label %while.end220, label %while.body211
+
+while.body211: ; preds = %while.body211, %if.then136.us
+ br i1 undef, label %while.end220, label %while.body211
+
+while.end220: ; preds = %while.body211, %if.then136.us
+ br label %for.cond246.outer
+
+for.cond246.outer: ; preds = %for.inc558, %for.cond394.preheader, %if.then274, %for.cond404.preheader, %while.end220
+ br label %for.cond246
+
+for.cond246: ; preds = %for.cond372.loopexit, %for.cond246.outer
+ br i1 undef, label %for.end562, label %if.end250
+
+if.end250: ; preds = %for.cond246
+ br i1 undef, label %if.end256, label %for.end562
+
+if.end256: ; preds = %if.end250
+ %cmp272 = icmp eq i32 undef, undef
+ br i1 %cmp272, label %if.then274, label %for.cond404.preheader
+
+for.cond404.preheader: ; preds = %if.end256
+ br i1 undef, label %for.cond246.outer, label %for.body409.lr.ph
+
+for.body409.lr.ph: ; preds = %for.cond404.preheader
+ br label %for.body409
+
+if.then274: ; preds = %if.end256
+ br i1 undef, label %for.cond246.outer, label %if.end309
+
+if.end309: ; preds = %if.then274
+ br i1 undef, label %for.cond372.loopexit, label %for.body361
+
+for.body361: ; preds = %for.body361, %if.end309
+ br i1 undef, label %for.cond372.loopexit, label %for.body361
+
+for.cond372.loopexit: ; preds = %for.body361, %if.end309
+ br i1 undef, label %for.cond394.preheader, label %for.cond246
+
+for.cond394.preheader: ; preds = %for.cond372.loopexit
+ br i1 undef, label %for.cond246.outer, label %for.body397
+
+for.body397: ; preds = %for.cond394.preheader
+ unreachable
+
+for.body409: ; preds = %for.inc558, %for.body409.lr.ph
+ %k.029 = phi i32 [ 1, %for.body409.lr.ph ], [ %inc559, %for.inc558 ]
+ br i1 undef, label %if.then412, label %if.else433
+
+if.then412: ; preds = %for.body409
+ br label %if.end440
+
+if.else433: ; preds = %for.body409
+ br label %if.end440
+
+if.end440: ; preds = %if.else433, %if.then412
+ br i1 undef, label %for.inc558, label %if.end461
+
+if.end461: ; preds = %if.end440
+ br i1 undef, label %for.cond528.loopexit, label %for.body517
+
+for.body517: ; preds = %for.body517, %if.end461
+ br i1 undef, label %for.cond528.loopexit, label %for.body517
+
+for.cond528.loopexit: ; preds = %for.body517, %if.end461
+ br label %for.inc558
+
+for.inc558: ; preds = %for.cond528.loopexit, %if.end440
+ %inc559 = add nsw i32 %k.029, 1
+ %cmp407 = icmp sgt i32 %inc559, undef
+ br i1 %cmp407, label %for.cond246.outer, label %for.body409
+
+for.end562: ; preds = %if.end250, %for.cond246
+ unreachable
+
+for.cond612: ; preds = %while.body119.lr.ph.lr.ph, %if.end115
+ unreachable
+}
+
+define void @test2() nounwind uwtable ssp {
+entry:
+ br i1 undef, label %for.end, label %for.body
+
+for.body: ; preds = %for.body, %entry
+ br i1 undef, label %for.end, label %for.body
+
+for.end: ; preds = %for.body, %entry
+ br i1 undef, label %for.end11, label %for.body3
+
+for.body3: ; preds = %for.end
+ unreachable
+
+for.end11: ; preds = %for.end
+ br i1 undef, label %while.body, label %while.end
+
+while.body: ; preds = %for.end11
+ unreachable
+
+while.end: ; preds = %for.end11
+ br i1 undef, label %if.end115, label %for.cond109
+
+for.cond109: ; preds = %while.end
+ unreachable
+
+if.end115: ; preds = %while.end
+ br i1 undef, label %while.body119.lr.ph.lr.ph, label %for.cond612
+
+while.body119.lr.ph.lr.ph: ; preds = %if.end115
+ br i1 undef, label %for.cond612, label %if.end123.us
+
+if.end123.us: ; preds = %while.body119.lr.ph.lr.ph
+ br label %for.cond132.us
+
+for.cond132.us: ; preds = %for.cond132.us, %if.end123.us
+ br i1 undef, label %if.then136.us, label %for.cond132.us
+
+if.then136.us: ; preds = %for.cond132.us
+ br i1 undef, label %while.end220, label %while.body211
+
+while.body211: ; preds = %while.body211, %if.then136.us
+ br i1 undef, label %while.end220, label %while.body211
+
+while.end220: ; preds = %while.body211, %if.then136.us
+ br label %for.cond246.outer
+
+for.cond246.outer: ; preds = %for.inc558, %for.cond394.preheader, %if.then274, %for.cond404.preheader, %while.end220
+ br label %for.cond246
+
+for.cond246: ; preds = %for.cond372.loopexit, %for.cond246.outer
+ br i1 undef, label %for.end562, label %if.end250
+
+if.end250: ; preds = %for.cond246
+ br i1 undef, label %if.end256, label %for.end562
+
+if.end256: ; preds = %if.end250
+ %0 = load i32* undef, align 4
+ br i1 undef, label %if.then274, label %for.cond404.preheader
+
+for.cond404.preheader: ; preds = %if.end256
+ %add406 = add i32 0, %0
+ br i1 undef, label %for.cond246.outer, label %for.body409.lr.ph
+
+for.body409.lr.ph: ; preds = %for.cond404.preheader
+ br label %for.body409
+
+if.then274: ; preds = %if.end256
+ br i1 undef, label %for.cond246.outer, label %if.end309
+
+if.end309: ; preds = %if.then274
+ br i1 undef, label %for.cond372.loopexit, label %for.body361
+
+for.body361: ; preds = %for.body361, %if.end309
+ br i1 undef, label %for.cond372.loopexit, label %for.body361
+
+for.cond372.loopexit: ; preds = %for.body361, %if.end309
+ br i1 undef, label %for.cond394.preheader, label %for.cond246
+
+for.cond394.preheader: ; preds = %for.cond372.loopexit
+ br i1 undef, label %for.cond246.outer, label %for.body397
+
+for.body397: ; preds = %for.cond394.preheader
+ unreachable
+
+for.body409: ; preds = %for.inc558, %for.body409.lr.ph
+ %k.029 = phi i32 [ 1, %for.body409.lr.ph ], [ %inc559, %for.inc558 ]
+ br i1 undef, label %if.then412, label %if.else433
+
+if.then412: ; preds = %for.body409
+ br label %if.end440
+
+if.else433: ; preds = %for.body409
+ br label %if.end440
+
+if.end440: ; preds = %if.else433, %if.then412
+ br i1 undef, label %for.inc558, label %if.end461
+
+if.end461: ; preds = %if.end440
+ br i1 undef, label %for.cond528.loopexit, label %for.body517
+
+for.body517: ; preds = %for.body517, %if.end461
+ br i1 undef, label %for.cond528.loopexit, label %for.body517
+
+for.cond528.loopexit: ; preds = %for.body517, %if.end461
+ br label %for.inc558
+
+for.inc558: ; preds = %for.cond528.loopexit, %if.end440
+ %inc559 = add nsw i32 %k.029, 1
+ %cmp407 = icmp sgt i32 %inc559, %add406
+ br i1 %cmp407, label %for.cond246.outer, label %for.body409
+
+for.end562: ; preds = %if.end250, %for.cond246
+ unreachable
+
+for.cond612: ; preds = %while.body119.lr.ph.lr.ph, %if.end115
+ unreachable
+}
+
+define void @test3() nounwind uwtable ssp {
+entry:
+ br i1 undef, label %for.end, label %for.body
+
+for.body: ; preds = %for.body, %entry
+ br i1 undef, label %for.end, label %for.body
+
+for.end: ; preds = %for.body, %entry
+ br i1 undef, label %for.end11, label %for.body3
+
+for.body3: ; preds = %for.end
+ unreachable
+
+for.end11: ; preds = %for.end
+ br i1 undef, label %while.body, label %while.end
+
+while.body: ; preds = %for.end11
+ unreachable
+
+while.end: ; preds = %for.end11
+ br i1 undef, label %if.end115, label %for.cond109
+
+for.cond109: ; preds = %while.end
+ unreachable
+
+if.end115: ; preds = %while.end
+ br i1 undef, label %while.body119.lr.ph.lr.ph, label %for.cond612
+
+while.body119.lr.ph.lr.ph: ; preds = %if.end115
+ br i1 undef, label %for.cond612, label %if.end123.us
+
+if.end123.us: ; preds = %while.body119.lr.ph.lr.ph
+ br label %for.cond132.us
+
+for.cond132.us: ; preds = %for.cond132.us, %if.end123.us
+ br i1 undef, label %if.then136.us, label %for.cond132.us
+
+if.then136.us: ; preds = %for.cond132.us
+ br i1 undef, label %while.end220, label %while.body211
+
+while.body211: ; preds = %while.body211, %if.then136.us
+ br i1 undef, label %while.end220, label %while.body211
+
+while.end220: ; preds = %while.body211, %if.then136.us
+ br label %for.cond246.outer
+
+for.cond246.outer: ; preds = %for.inc558, %for.cond394.preheader, %if.then274, %for.cond404.preheader, %while.end220
+ br label %for.cond246
+
+for.cond246: ; preds = %for.cond372.loopexit, %for.cond246.outer
+ br i1 undef, label %for.end562, label %if.end250
+
+if.end250: ; preds = %for.cond246
+ br i1 undef, label %if.end256, label %for.end562
+
+if.end256: ; preds = %if.end250
+ br i1 undef, label %if.then274, label %for.cond404.preheader
+
+for.cond404.preheader: ; preds = %if.end256
+ br i1 undef, label %for.cond246.outer, label %for.body409.lr.ph
+
+for.body409.lr.ph: ; preds = %for.cond404.preheader
+ br label %for.body409
+
+if.then274: ; preds = %if.end256
+ br i1 undef, label %for.cond246.outer, label %if.end309
+
+if.end309: ; preds = %if.then274
+ br i1 undef, label %for.cond372.loopexit, label %for.body361
+
+for.body361: ; preds = %for.body361, %if.end309
+ br i1 undef, label %for.cond372.loopexit, label %for.body361
+
+for.cond372.loopexit: ; preds = %for.body361, %if.end309
+ br i1 undef, label %for.cond394.preheader, label %for.cond246
+
+for.cond394.preheader: ; preds = %for.cond372.loopexit
+ br i1 undef, label %for.cond246.outer, label %for.body397
+
+for.body397: ; preds = %for.cond394.preheader
+ unreachable
+
+for.body409: ; preds = %for.inc558, %for.body409.lr.ph
+ br i1 undef, label %if.then412, label %if.else433
+
+if.then412: ; preds = %for.body409
+ br label %if.end440
+
+if.else433: ; preds = %for.body409
+ br label %if.end440
+
+if.end440: ; preds = %if.else433, %if.then412
+ br i1 undef, label %for.inc558, label %if.end461
+
+if.end461: ; preds = %if.end440
+ br i1 undef, label %for.cond528.loopexit, label %for.body517
+
+for.body517: ; preds = %for.body517, %if.end461
+ br i1 undef, label %for.cond528.loopexit, label %for.body517
+
+for.cond528.loopexit: ; preds = %for.body517, %if.end461
+ br label %for.inc558
+
+for.inc558: ; preds = %for.cond528.loopexit, %if.end440
+ br i1 undef, label %for.cond246.outer, label %for.body409
+
+for.end562: ; preds = %if.end250, %for.cond246
+ unreachable
+
+for.cond612: ; preds = %while.body119.lr.ph.lr.ph, %if.end115
+ unreachable
+}
+
+define void @test4() nounwind uwtable ssp {
+entry:
+ br i1 undef, label %if.end8, label %if.else
+
+if.else: ; preds = %entry
+ br label %if.end8
+
+if.end8: ; preds = %if.else, %entry
+ br i1 undef, label %if.end26, label %if.else22
+
+if.else22: ; preds = %if.end8
+ br label %if.end26
+
+if.end26: ; preds = %if.else22, %if.end8
+ br i1 undef, label %if.end35, label %if.else31
+
+if.else31: ; preds = %if.end26
+ br label %if.end35
+
+if.end35: ; preds = %if.else31, %if.end26
+ br i1 undef, label %for.end226, label %for.body.lr.ph
+
+for.body.lr.ph: ; preds = %if.end35
+ br label %for.body48
+
+for.body48: ; preds = %for.inc221, %for.body.lr.ph
+ br i1 undef, label %for.inc221, label %for.body65.lr.ph
+
+for.body65.lr.ph: ; preds = %for.body48
+ %0 = load i32* undef, align 4
+ br label %for.body65.us
+
+for.body65.us: ; preds = %for.inc219.us, %for.body65.lr.ph
+ %k.09.us = phi i32 [ %inc.us, %for.inc219.us ], [ 1, %for.body65.lr.ph ]
+ %idxprom66.us = sext i32 %k.09.us to i64
+ br i1 undef, label %for.inc219.us, label %if.end72.us
+
+if.end72.us: ; preds = %for.body65.us
+ br i1 undef, label %if.end93.us, label %if.then76.us
+
+if.then76.us: ; preds = %if.end72.us
+ br label %if.end93.us
+
+if.end93.us: ; preds = %if.then76.us, %if.end72.us
+ br i1 undef, label %if.end110.us, label %for.inc219.us
+
+if.end110.us: ; preds = %if.end93.us
+ br i1 undef, label %for.inc219.us, label %for.body142.us
+
+for.body142.us: ; preds = %for.cond139.loopexit.us, %if.end110.us
+ br label %for.cond152.us
+
+for.cond152.us: ; preds = %for.cond152.us, %for.body142.us
+ br i1 undef, label %for.cond139.loopexit.us, label %for.cond152.us
+
+for.inc219.us: ; preds = %for.cond139.loopexit.us, %if.end110.us, %if.end93.us, %for.body65.us
+ %inc.us = add nsw i32 %k.09.us, 1
+ %cmp64.us = icmp sgt i32 %inc.us, %0
+ br i1 %cmp64.us, label %for.inc221, label %for.body65.us
+
+for.cond139.loopexit.us: ; preds = %for.cond152.us
+ br i1 undef, label %for.inc219.us, label %for.body142.us
+
+for.inc221: ; preds = %for.inc219.us, %for.body48
+ br label %for.body48
+
+for.end226: ; preds = %if.end35
+ ret void
+}
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