[llvm-commits] [llvm] r109419 - in /llvm/trunk: lib/Analysis/ScalarEvolutionExpander.cpp test/Transforms/IndVarSimplify/crash.ll
Dan Gohman
gohman at apple.com
Mon Jul 26 11:28:14 PDT 2010
Author: djg
Date: Mon Jul 26 13:28:14 2010
New Revision: 109419
URL: http://llvm.org/viewvc/llvm-project?rev=109419&view=rev
Log:
Fix SCEVExpander::visitAddRecExpr so that it remembers the induction variable
it inserted rather than using LoopInfo::getCanonicalInductionVariable to
rediscover it, since that doesn't work on non-canonical loops. This fixes
infinite recurrsion on such loops; PR7562.
Modified:
llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
llvm/trunk/test/Transforms/IndVarSimplify/crash.ll
Modified: llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp?rev=109419&r1=109418&r2=109419&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp Mon Jul 26 13:28:14 2010
@@ -1112,21 +1112,13 @@
SE.getUnknown(expand(Rest))));
}
- // {0,+,1} --> Insert a canonical induction variable into the loop!
- if (S->isAffine() && S->getOperand(1)->isOne()) {
- // If there's a canonical IV, just use it.
- if (CanonicalIV) {
- assert(Ty == SE.getEffectiveSCEVType(CanonicalIV->getType()) &&
- "IVs with types different from the canonical IV should "
- "already have been handled!");
- return CanonicalIV;
- }
-
+ // If we don't yet have a canonical IV, create one.
+ if (!CanonicalIV) {
// Create and insert the PHI node for the induction variable in the
// specified loop.
BasicBlock *Header = L->getHeader();
- PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
- rememberInstruction(PN);
+ CanonicalIV = PHINode::Create(Ty, "indvar", Header->begin());
+ rememberInstruction(CanonicalIV);
Constant *One = ConstantInt::get(Ty, 1);
for (pred_iterator HPI = pred_begin(Header), HPE = pred_end(Header);
@@ -1135,40 +1127,45 @@
if (L->contains(HP)) {
// Insert a unit add instruction right before the terminator
// corresponding to the back-edge.
- Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
- HP->getTerminator());
+ Instruction *Add = BinaryOperator::CreateAdd(CanonicalIV, One,
+ "indvar.next",
+ HP->getTerminator());
rememberInstruction(Add);
- PN->addIncoming(Add, HP);
+ CanonicalIV->addIncoming(Add, HP);
} else {
- PN->addIncoming(Constant::getNullValue(Ty), HP);
+ CanonicalIV->addIncoming(Constant::getNullValue(Ty), HP);
}
}
}
+ // {0,+,1} --> Insert a canonical induction variable into the loop!
+ if (S->isAffine() && S->getOperand(1)->isOne()) {
+ assert(Ty == SE.getEffectiveSCEVType(CanonicalIV->getType()) &&
+ "IVs with types different from the canonical IV should "
+ "already have been handled!");
+ return CanonicalIV;
+ }
+
// {0,+,F} --> {0,+,1} * F
- // Get the canonical induction variable I for this loop.
- Value *I = CanonicalIV ?
- CanonicalIV :
- getOrInsertCanonicalInductionVariable(L, Ty);
// If this is a simple linear addrec, emit it now as a special case.
if (S->isAffine()) // {0,+,F} --> i*F
return
expand(SE.getTruncateOrNoop(
- SE.getMulExpr(SE.getUnknown(I),
+ SE.getMulExpr(SE.getUnknown(CanonicalIV),
SE.getNoopOrAnyExtend(S->getOperand(1),
- I->getType())),
+ CanonicalIV->getType())),
Ty));
// If this is a chain of recurrences, turn it into a closed form, using the
// folders, then expandCodeFor the closed form. This allows the folders to
// simplify the expression without having to build a bunch of special code
// into this folder.
- const SCEV *IH = SE.getUnknown(I); // Get I as a "symbolic" SCEV.
+ const SCEV *IH = SE.getUnknown(CanonicalIV); // Get I as a "symbolic" SCEV.
// Promote S up to the canonical IV type, if the cast is foldable.
const SCEV *NewS = S;
- const SCEV *Ext = SE.getNoopOrAnyExtend(S, I->getType());
+ const SCEV *Ext = SE.getNoopOrAnyExtend(S, CanonicalIV->getType());
if (isa<SCEVAddRecExpr>(Ext))
NewS = Ext;
Modified: llvm/trunk/test/Transforms/IndVarSimplify/crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/crash.ll?rev=109419&r1=109418&r2=109419&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/crash.ll (original)
+++ llvm/trunk/test/Transforms/IndVarSimplify/crash.ll Mon Jul 26 13:28:14 2010
@@ -1,4 +1,5 @@
; RUN: opt -indvars %s -disable-output
+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"
declare i32 @putchar(i8) nounwind
@@ -17,3 +18,38 @@
; <label>:6 ; preds = %1
ret void
}
+
+; PR7562
+define void @fannkuch() nounwind {
+entry: ; preds = %entry
+ br label %bb12
+
+bb12: ; preds = %bb29, %entry
+ %i.1 = phi i32 [ undef, %entry ], [ %i.0, %bb29 ] ; <i32> [#uses=2]
+ %r.1 = phi i32 [ undef, %entry ], [ %r.0, %bb29 ] ; <i32> [#uses=2]
+ br i1 undef, label %bb13, label %bb24
+
+bb13: ; preds = %bb12
+ br label %bb24
+
+bb24: ; preds = %bb30, %bb13, %bb12
+ %i.2 = phi i32 [ %i.1, %bb13 ], [ %i.0, %bb30 ], [ %i.1, %bb12 ] ; <i32> [#uses=1]
+ %r.0 = phi i32 [ %r.1, %bb13 ], [ %2, %bb30 ], [ %r.1, %bb12 ] ; <i32> [#uses=3]
+ br label %bb28
+
+bb27: ; preds = %bb28
+ %0 = add nsw i32 %i.0, 1 ; <i32> [#uses=1]
+ br label %bb28
+
+bb28: ; preds = %bb27, %bb26
+ %i.0 = phi i32 [ %i.2, %bb24 ], [ %0, %bb27 ] ; <i32> [#uses=4]
+ %1 = icmp slt i32 %i.0, %r.0 ; <i1> [#uses=1]
+ br i1 %1, label %bb27, label %bb29
+
+bb29: ; preds = %bb28
+ br i1 undef, label %bb12, label %bb30
+
+bb30: ; preds = %bb29
+ %2 = add nsw i32 %r.0, 1 ; <i32> [#uses=1]
+ br label %bb24
+}
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