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Crash less. The i64 restriction in BinomialCoefficient caused some problems

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with code that was expecting different bit widths for different values.

Make getTruncateOrZeroExtend a method on ScalarEvolution, and use it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52248 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2008-06-13 04:38:55 +00:00
parent 52ed363fd3
commit 6f8abf929a
3 changed files with 78 additions and 24 deletions
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5
include/llvm/Analysis/ScalarEvolution.h
View File

@ -253,6 +253,11 @@ namespace llvm {
SCEVHandle getMinusSCEV(const SCEVHandle &LHS,
const SCEVHandle &RHS);
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// extended, it is zero extended.
SCEVHandle getTruncateOrZeroExtend(const SCEVHandle &V, const Type *Ty);
/// getIntegerSCEV - Given an integer or FP type, create a constant for the
/// specified signed integer value and return a SCEV for the constant.
SCEVHandle getIntegerSCEV(int Val, const Type *Ty);

54
lib/Analysis/ScalarEvolution.cpp
View File

@ -499,21 +499,6 @@ SCEVHandle ScalarEvolution::getIntegerSCEV(int Val, const Type *Ty) {
return getUnknown(C);
}
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion of the
/// input value to the specified type. If the type must be extended, it is zero
/// extended.
static SCEVHandle getTruncateOrZeroExtend(const SCEVHandle &V, const Type *Ty,
ScalarEvolution &SE) {
const Type *SrcTy = V->getType();
assert(SrcTy->isInteger() && Ty->isInteger() &&
"Cannot truncate or zero extend with non-integer arguments!");
if (SrcTy->getPrimitiveSizeInBits() == Ty->getPrimitiveSizeInBits())
return V; // No conversion
if (SrcTy->getPrimitiveSizeInBits() > Ty->getPrimitiveSizeInBits())
return SE.getTruncateExpr(V, Ty);
return SE.getZeroExtendExpr(V, Ty);
}
/// getNegativeSCEV - Return a SCEV corresponding to -V = -1*V
///
SCEVHandle ScalarEvolution::getNegativeSCEV(const SCEVHandle &V) {
@ -585,7 +570,7 @@ static SCEVHandle BinomialCoefficient(SCEVHandle It, unsigned K,
#endif
const IntegerType *DividendTy = IntegerType::get(DividendBits);
const SCEVHandle ExIt = SE.getZeroExtendExpr(It, DividendTy);
const SCEVHandle ExIt = SE.getTruncateOrZeroExtend(It, DividendTy);
// The final number of bits we need to perform the division is the maximum of
// dividend and divisor bitwidths.
@ -607,7 +592,12 @@ static SCEVHandle BinomialCoefficient(SCEVHandle It, unsigned K,
Dividend *= N-(K-1);
if (DividendTy != DivisionTy)
Dividend = Dividend.zext(DivisionTy->getBitWidth());
return SE.getConstant(Dividend.udiv(Divisor).trunc(It->getBitWidth()));
APInt Result = Dividend.udiv(Divisor);
if (Result.getBitWidth() != It->getBitWidth())
Result = Result.trunc(It->getBitWidth());
return SE.getConstant(Result);
}
SCEVHandle Dividend = ExIt;
@ -615,11 +605,12 @@ static SCEVHandle BinomialCoefficient(SCEVHandle It, unsigned K,
Dividend =
SE.getMulExpr(Dividend,
SE.getMinusSCEV(ExIt, SE.getIntegerSCEV(i, DividendTy)));
if (DividendTy != DivisionTy)
Dividend = SE.getZeroExtendExpr(Dividend, DivisionTy);
return
SE.getTruncateExpr(SE.getUDivExpr(Dividend, SE.getConstant(Divisor)),
It->getType());
return SE.getTruncateOrZeroExtend(
SE.getUDivExpr(
SE.getTruncateOrZeroExtend(Dividend, DivisionTy),
SE.getConstant(Divisor)
), It->getType());
}
/// evaluateAtIteration - Return the value of this chain of recurrences at
@ -703,6 +694,21 @@ SCEVHandle ScalarEvolution::getSignExtendExpr(const SCEVHandle &Op, const Type *
return Result;
}
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// extended, it is zero extended.
SCEVHandle ScalarEvolution::getTruncateOrZeroExtend(const SCEVHandle &V,
const Type *Ty) {
const Type *SrcTy = V->getType();
assert(SrcTy->isInteger() && Ty->isInteger() &&
"Cannot truncate or zero extend with non-integer arguments!");
if (SrcTy->getPrimitiveSizeInBits() == Ty->getPrimitiveSizeInBits())
return V; // No conversion
if (SrcTy->getPrimitiveSizeInBits() > Ty->getPrimitiveSizeInBits())
return getTruncateExpr(V, Ty);
return getZeroExtendExpr(V, Ty);
}
// get - Get a canonical add expression, or something simpler if possible.
SCEVHandle ScalarEvolution::getAddExpr(std::vector<SCEVHandle> &Ops) {
assert(!Ops.empty() && "Cannot get empty add!");
@ -2432,8 +2438,8 @@ SCEVHandle ScalarEvolutionsImpl::getSCEVAtScope(SCEV *V, const Loop *L) {
// loop iterates. Compute this now.
SCEVHandle IterationCount = getIterationCount(AddRec->getLoop());
if (IterationCount == UnknownValue) return UnknownValue;
IterationCount = getTruncateOrZeroExtend(IterationCount,
AddRec->getType(), SE);
IterationCount = SE.getTruncateOrZeroExtend(IterationCount,
AddRec->getType());
// If the value is affine, simplify the expression evaluation to just
// Start + Step*IterationCount.

43
test/Analysis/ScalarEvolution/2008-06-12-BinomialInt64.ll Normal file
View File

@ -0,0 +1,43 @@
; RUN: llvm-as < %s | opt -analyze -scalar-evolution 2>/dev/null
; PR2433
define i32 @main1(i32 %argc, i8** %argv) nounwind {
entry:
br i1 false, label %bb10, label %bb23
bb10: ; preds = %bb10, %entry
%accum.03 = phi i64 [ %tmp14, %bb10 ], [ 0, %entry ] ; <i64> [#uses=1]
%i.02 = phi i32 [ %tmp16, %bb10 ], [ 0, %entry ] ; <i32> [#uses=1]
%d.1.01 = phi i64 [ %tmp5.i, %bb10 ], [ 0, %entry ] ; <i64> [#uses=1]
%tmp5.i = add i64 %d.1.01, 1 ; <i64> [#uses=2]
%tmp14 = add i64 %accum.03, %tmp5.i ; <i64> [#uses=2]
%tmp16 = add i32 %i.02, 1 ; <i32> [#uses=2]
%tmp20 = icmp slt i32 %tmp16, 0 ; <i1> [#uses=1]
br i1 %tmp20, label %bb10, label %bb23
bb23: ; preds = %bb10, %entry
%accum.0.lcssa = phi i64 [ 0, %entry ], [ %tmp14, %bb10 ] ; <i64> [#uses=0]
ret i32 0
}
define i32 @main2(i32 %argc, i8** %argv) {
entry:
%tmp8 = tail call i32 @atoi( i8* null ) nounwind readonly ; <i32> [#uses=1]
br i1 false, label %bb9, label %bb21
bb9: ; preds = %bb9, %entry
%accum.03 = phi i64 [ %tmp12, %bb9 ], [ 0, %entry ] ; <i64> [#uses=1]
%i.02 = phi i32 [ %tmp14, %bb9 ], [ 0, %entry ] ; <i32> [#uses=1]
%d.1.01 = phi i64 [ %tmp4.i, %bb9 ], [ 0, %entry ] ; <i64> [#uses=1]
%tmp4.i = add i64 %d.1.01, 1 ; <i64> [#uses=2]
%tmp12 = add i64 %accum.03, %tmp4.i ; <i64> [#uses=2]
%tmp14 = add i32 %i.02, 1 ; <i32> [#uses=2]
%tmp18 = icmp slt i32 %tmp14, %tmp8 ; <i1> [#uses=1]
br i1 %tmp18, label %bb9, label %bb21
bb21: ; preds = %bb9, %entry
%accum.0.lcssa = phi i64 [ 0, %entry ], [ %tmp12, %bb9 ] ; <i64> [#uses=0]
ret i32 0
}
declare i32 @atoi(i8*) nounwind readonly