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6717150: improper constant folding of subnormal strictfp multiplications and divides

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Suppress constant folding of double divides and multiplications on ia32

Reviewed-by: never
This commit is contained in:
Chuck Rasbold 2008-10-14 06:58:58 -07:00
parent e585263735
commit 0dac6431d2
2 changed files with 21 additions and 6 deletions
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17
hotspot/src/share/vm/opto/divnode.cpp
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@ -710,11 +710,18 @@ const Type *DivDNode::Value( PhaseTransform *phase ) const {
if( t2 == TypeD::ONE )
return t1;
// If divisor is a constant and not zero, divide them numbers
if( t1->base() == Type::DoubleCon &&
t2->base() == Type::DoubleCon &&
t2->getd() != 0.0 ) // could be negative zero
return TypeD::make( t1->getd()/t2->getd() );
#if defined(IA32)
if (!phase->C->method()->is_strict())
// Can't trust native compilers to properly fold strict double
// division with round-to-zero on this platform.
#endif
{
// If divisor is a constant and not zero, divide them numbers
if( t1->base() == Type::DoubleCon &&
t2->base() == Type::DoubleCon &&
t2->getd() != 0.0 ) // could be negative zero
return TypeD::make( t1->getd()/t2->getd() );
}
// If the dividend is a constant zero
// Note: if t1 and t2 are zero then result is NaN (JVMS page 213)