Change SCEVExpander's expandCodeFor to provide more flexibility

with the persistent insertion point, and change IndVars to make
use of it. This fixes a bug where IndVars was holding on to a
stale insertion point and forcing the SCEVExpander to continue to
use it.

This fixes PR4038.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69892 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-04-23 15:16:49 +00:00
parent b1f321b553
commit 752ec7da50
4 changed files with 48 additions and 19 deletions

View File

@ -71,13 +71,23 @@ namespace llvm {
InsertedInstructions.insert(I);
}
void setInsertionPoint(BasicBlock::iterator NewIP) { InsertPt = NewIP; }
BasicBlock::iterator getInsertionPoint() const { return InsertPt; }
/// expandCodeFor - Insert code to directly compute the specified SCEV
/// expression into the program. The inserted code is inserted into the
/// SCEVExpander's current insertion point.
Value *expandCodeFor(SCEVHandle SH, const Type *Ty);
/// expandCodeFor - Insert code to directly compute the specified SCEV
/// expression into the program. The inserted code is inserted into the
/// specified block.
Value *expandCodeFor(SCEVHandle SH, const Type *Ty,
BasicBlock::iterator IP);
BasicBlock::iterator IP) {
setInsertionPoint(IP);
return expandCodeFor(SH, Ty);
}
/// InsertCastOfTo - Insert a cast of V to the specified type, doing what
/// we can to share the casts.

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@ -332,12 +332,10 @@ Value *SCEVExpander::visitUMaxExpr(const SCEVUMaxExpr *S) {
return LHS;
}
Value *SCEVExpander::expandCodeFor(SCEVHandle SH, const Type *Ty,
BasicBlock::iterator IP) {
Value *SCEVExpander::expandCodeFor(SCEVHandle SH, const Type *Ty) {
// Expand the code for this SCEV.
assert(SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(SH->getType()) &&
"non-trivial casts should be done with the SCEVs directly!");
InsertPt = IP;
Value *V = expand(SH);
return InsertNoopCastOfTo(V, Ty);
}

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@ -543,8 +543,7 @@ static Value *getSignExtendedTruncVar(const SCEVAddRecExpr *AR,
ScalarEvolution *SE,
const Type *LargestType, Loop *L,
const Type *myType,
SCEVExpander &Rewriter,
BasicBlock::iterator InsertPt) {
SCEVExpander &Rewriter) {
SCEVHandle ExtendedStart =
SE->getSignExtendExpr(AR->getStart(), LargestType);
SCEVHandle ExtendedStep =
@ -553,15 +552,14 @@ static Value *getSignExtendedTruncVar(const SCEVAddRecExpr *AR,
SE->getAddRecExpr(ExtendedStart, ExtendedStep, L);
if (LargestType != myType)
ExtendedAddRec = SE->getTruncateExpr(ExtendedAddRec, myType);
return Rewriter.expandCodeFor(ExtendedAddRec, myType, InsertPt);
return Rewriter.expandCodeFor(ExtendedAddRec, myType);
}
static Value *getZeroExtendedTruncVar(const SCEVAddRecExpr *AR,
ScalarEvolution *SE,
const Type *LargestType, Loop *L,
const Type *myType,
SCEVExpander &Rewriter,
BasicBlock::iterator InsertPt) {
SCEVExpander &Rewriter) {
SCEVHandle ExtendedStart =
SE->getZeroExtendExpr(AR->getStart(), LargestType);
SCEVHandle ExtendedStep =
@ -570,7 +568,7 @@ static Value *getZeroExtendedTruncVar(const SCEVAddRecExpr *AR,
SE->getAddRecExpr(ExtendedStart, ExtendedStep, L);
if (LargestType != myType)
ExtendedAddRec = SE->getTruncateExpr(ExtendedAddRec, myType);
return Rewriter.expandCodeFor(ExtendedAddRec, myType, InsertPt);
return Rewriter.expandCodeFor(ExtendedAddRec, myType);
}
/// allUsesAreSameTyped - See whether all Uses of I are instructions
@ -699,6 +697,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
// recurrences in terms of the induction variable. Start with the auxillary
// induction variables, and recursively rewrite any of their uses.
BasicBlock::iterator InsertPt = Header->getFirstNonPHI();
Rewriter.setInsertionPoint(InsertPt);
// If there were induction variables of other sizes, cast the primary
// induction variable to the right size for them, avoiding the need for the
@ -718,7 +717,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
while (!IndVars.empty()) {
PHINode *PN = IndVars.back().first;
const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(IndVars.back().second);
Value *NewVal = Rewriter.expandCodeFor(AR, PN->getType(), InsertPt);
Value *NewVal = Rewriter.expandCodeFor(AR, PN->getType());
DOUT << "INDVARS: Rewrote IV '" << *AR << "' " << *PN
<< " into = " << *NewVal << "\n";
NewVal->takeName(PN);
@ -732,7 +731,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
Instruction *UInst = dyn_cast<Instruction>(*UI);
if (UInst && isa<SExtInst>(UInst) && NoSignedWrap) {
Value *TruncIndVar = getSignExtendedTruncVar(AR, SE, LargestType, L,
UInst->getType(), Rewriter, InsertPt);
UInst->getType(), Rewriter);
UInst->replaceAllUsesWith(TruncIndVar);
DeadInsts.insert(UInst);
}
@ -753,8 +752,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
SExtInst* oldSext = dyn_cast<SExtInst>(UInst->use_begin());
uint64_t truncSize = oldSext->getType()->getPrimitiveSizeInBits();
Value *TruncIndVar = getSignExtendedTruncVar(AR, SE, LargestType,
L, oldSext->getType(), Rewriter,
InsertPt);
L, oldSext->getType(), Rewriter);
APInt APnewAddRHS = APInt(AddRHS->getValue()).sext(newBitSize);
if (newBitSize > truncSize)
APnewAddRHS = APnewAddRHS.trunc(truncSize);
@ -784,8 +782,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
SExtInst* oldSext = dyn_cast<SExtInst>(UInst->use_begin());
uint64_t truncSize = oldSext->getType()->getPrimitiveSizeInBits();
Value *TruncIndVar = getSignExtendedTruncVar(AR, SE, LargestType,
L, oldSext->getType(), Rewriter,
InsertPt);
L, oldSext->getType(), Rewriter);
APInt APnewOrRHS = APInt(RHS->getValue()).sext(newBitSize);
if (newBitSize > truncSize)
APnewOrRHS = APnewOrRHS.trunc(truncSize);
@ -805,7 +802,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
// A zext of a signed variable known not to overflow is still safe.
if (UInst && isa<ZExtInst>(UInst) && (NoUnsignedWrap || NoSignedWrap)) {
Value *TruncIndVar = getZeroExtendedTruncVar(AR, SE, LargestType, L,
UInst->getType(), Rewriter, InsertPt);
UInst->getType(), Rewriter);
UInst->replaceAllUsesWith(TruncIndVar);
DeadInsts.insert(UInst);
}
@ -822,7 +819,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
ZExtInst* oldZext = dyn_cast<ZExtInst>(UInst->use_begin());
uint64_t truncSize = oldZext->getType()->getPrimitiveSizeInBits();
Value *TruncIndVar = getSignExtendedTruncVar(AR, SE, LargestType,
L, oldZext->getType(), Rewriter, InsertPt);
L, oldZext->getType(), Rewriter);
APInt APnewAndRHS = APInt(AndRHS->getValue()).zext(newBitSize);
if (newBitSize > truncSize)
APnewAndRHS = APnewAndRHS.trunc(truncSize);
@ -858,7 +855,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
ZExtInst* oldZext = dyn_cast<ZExtInst>(UInst2->use_begin());
uint64_t truncSize = oldZext->getType()->getPrimitiveSizeInBits();
Value *TruncIndVar = getSignExtendedTruncVar(AR, SE, LargestType,
L, oldZext->getType(), Rewriter, InsertPt);
L, oldZext->getType(), Rewriter);
ConstantInt* AndRHS = dyn_cast<ConstantInt>(UInst2->getOperand(1));
APInt APnewAddRHS = APInt(AddRHS->getValue()).zext(newBitSize);
if (newBitSize > truncSize)

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@ -1,5 +1,6 @@
; RUN: llvm-as < %s | opt -indvars -disable-output
; PR4009
; PR4038
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
target triple = "i386-pc-linux-gnu"
@ -21,4 +22,27 @@ loop: ; preds = %loop, %if.else
br label %loop
}
define void @safe_bcopy_4038(i8* %from, i8* %to, i32 %size) nounwind {
entry:
br i1 false, label %if.else, label %if.then12
if.then12: ; preds = %entry
ret void
if.else: ; preds = %entry
%sub.ptr.rhs.cast40 = ptrtoint i8* %from to i32 ; <i32> [#uses=1]
br label %if.end54
if.end54: ; preds = %if.end54, %if.else
%sub.ptr4912.pn = phi i8* [ %sub.ptr4912, %if.end54 ], [ null, %if.else ] ; <i8*> [#uses=1]
%sub.ptr7 = phi i8* [ %sub.ptr, %if.end54 ], [ null, %if.else ] ; <i8*> [#uses=2]
%sub.ptr.rhs.cast46.pn = ptrtoint i8* %from to i32 ; <i32> [#uses=1]
%sub.ptr.lhs.cast45.pn = ptrtoint i8* %to to i32 ; <i32> [#uses=1]
%sub.ptr.sub47.pn = sub i32 %sub.ptr.rhs.cast46.pn, %sub.ptr.lhs.cast45.pn ; <i32> [#uses=1]
%sub.ptr4912 = getelementptr i8* %sub.ptr4912.pn, i32 %sub.ptr.sub47.pn ; <i8*> [#uses=2]
tail call void @bcopy(i8* %sub.ptr4912, i8* %sub.ptr7, i32 0) nounwind
%sub.ptr = getelementptr i8* %sub.ptr7, i32 %sub.ptr.rhs.cast40 ; <i8*> [#uses=1]
br label %if.end54
}
declare void @bcopy(i8* nocapture) nounwind