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Fix undefined behavior in AArch64

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A64Imms::isLogicalImmBits and A64Imms::isLogicalImm will attempt to
execute shifts that perform undefined behavior. Instead of attempting
to perform the 64-bit rotation, treat it as a no-op.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179317 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Majnemer 2013-04-11 20:13:52 +00:00
parent 59b11c415e
commit bae6d527df
1 changed files with 11 additions and 7 deletions
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18
lib/Target/AArch64/Utils/AArch64BaseInfo.cpp
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@ -981,8 +981,11 @@ bool A64Imms::isLogicalImm(unsigned RegWidth, uint64_t Imm, uint32_t &Bits) {
Rotation = RepeatWidth - Rotation;
}
uint64_t ReplicatedOnes = (ReplicatedMask >> Rotation)
| ((ReplicatedMask << (RepeatWidth - Rotation)) & RepeatMask);
uint64_t ReplicatedOnes = ReplicatedMask;
if (Rotation != 0 && Rotation != 64)
ReplicatedOnes = (ReplicatedMask >> Rotation)
| ((ReplicatedMask << (RepeatWidth - Rotation)) & RepeatMask);
// Of course, they may not actually be ones, so we have to check that:
if (!isMask_64(ReplicatedOnes))
continue;
@ -1051,13 +1054,14 @@ bool A64Imms::isLogicalImmBits(unsigned RegWidth, uint32_t Bits,
int Rotation = (ImmR & (Width - 1));
uint64_t Mask = (1ULL << Num1s) - 1;
uint64_t WidthMask = Width == 64 ? -1 : (1ULL << Width) - 1;
Mask = (Mask >> Rotation)
| ((Mask << (Width - Rotation)) & WidthMask);
if (Rotation != 0 && Rotation != 64)
Mask = (Mask >> Rotation)
| ((Mask << (Width - Rotation)) & WidthMask);
Imm = 0;
for (unsigned i = 0; i < RegWidth / Width; ++i) {
Imm |= Mask;
Imm = Mask;
for (unsigned i = 1; i < RegWidth / Width; ++i) {
Mask <<= Width;
Imm |= Mask;
}
return true;