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llvm-stress: stop abusing ConstantFP::get()

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ConstantFP::get(Type*, double) is unreliably host-specific:
it can't handle a type like PPC128 on an x86 host. It even
has a comment to that effect: "This should only be used for
simple constant values like 2.0/1.0 etc, that are
known-valid both as host double and as the target format."

Instead, use APFloat. While we're at it, randomize the floating
point value more thoroughly; it was previously limited
to the range 0 to 2**19 - 1.

PR12451.

llvm-svn: 154446
This commit is contained in:
Dylan Noblesmith 2012-04-10 22:44:51 +00:00
parent 2e2de248b0
commit 1e0746761c
1 changed files with 29 additions and 5 deletions
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34
tools/llvm-stress/llvm-stress.cpp
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@ -60,14 +60,28 @@ class Random {
public: public:
/// C'tor /// C'tor
Random(unsigned _seed):Seed(_seed) {} Random(unsigned _seed):Seed(_seed) {}
/// Return the next random value.
unsigned Rand() { /// Return a random integer, up to a
unsigned Val = Seed + 0x000b07a1; /// maximum of 2**19 - 1.
uint32_t Rand() {
uint32_t Val = Seed + 0x000b07a1;
Seed = (Val * 0x3c7c0ac1); Seed = (Val * 0x3c7c0ac1);
// Only lowest 19 bits are random-ish. // Only lowest 19 bits are random-ish.
return Seed & 0x7ffff; return Seed & 0x7ffff;
} }
/// Return a random 32 bit integer.
uint32_t Rand32() {
uint32_t Val = Rand();
Val &= 0xffff;
return Val | (Rand() << 16);
}
/// Return a random 64 bit integer.
uint64_t Rand64() {
uint64_t Val = Rand32();
return Val | (uint64_t(Rand32()) << 32);
}
private: private:
unsigned Seed; unsigned Seed;
}; };
@ -348,10 +362,20 @@ struct ConstModifier: public Modifier {
} }
if (Ty->isFloatingPointTy()) { if (Ty->isFloatingPointTy()) {
// Generate 128 random bits, the size of the (currently)
// largest floating-point types.
uint64_t RandomBits[2];
for (unsigned i = 0; i < 2; ++i)
RandomBits[i] = Ran->Rand64();
APInt RandomInt(Ty->getPrimitiveSizeInBits(), makeArrayRef(RandomBits));
bool isIEEE = !Ty->isX86_FP80Ty() && !Ty->isPPC_FP128Ty();
APFloat RandomFloat(RandomInt, isIEEE);
if (Ran->Rand() & 1) if (Ran->Rand() & 1)
return PT->push_back(ConstantFP::getNullValue(Ty)); return PT->push_back(ConstantFP::getNullValue(Ty));
return PT->push_back(ConstantFP::get(Ty, return PT->push_back(ConstantFP::get(Ty->getContext(), RandomFloat));
static_cast<double>(1)/Ran->Rand()));
} }
if (Ty->isIntegerTy()) { if (Ty->isIntegerTy()) {