(0.21.0) Fixed imm value for addis and lis #9948
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addis and lis accept a signed 16 bit value as an immediate. They are passed into generateTrg1Src1ImmInstruction as signed 32 bit values. In some edge cases, the sign extension was not handled properly. In most cases this was due to the value being incremented after sign extension. In other cases it was due to an unnecessary mask clearing the upper 16 bits. One case in genInstanceOfOrCheckCastSuperClassTest was handled incorrectly. addis should be used instead of lis to reconstruct the 32 bit immediate value to be added. For cases where the TOC offset is unusually large, I put in an assert instead of generating instructions. The reasoning was TOC offsets of this size should never occur so those code paths would never be tested. Also TOC offsets of that size are likely an indication of a problem elsewhere. Closes: eclipse-openj9#9612 Signed-off-by: jimmyk <jimmyk@ca.ibm.com>
pshipton
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This is a dup of #9950 |
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pshipton
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Jun 19, 2020
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addis and lis accept a signed 16 bit value as an immediate. They are passed
into generateTrg1Src1ImmInstruction as signed 32 bit values. In some edge
cases, the sign extension was not handled properly. In most cases this was
due to the value being incremented after sign extension. In other cases it
was due to an unnecessary mask clearing the upper 16 bits.
One case in genInstanceOfOrCheckCastSuperClassTest was handled incorrectly.
addis should be used instead of lis to reconstruct the 32 bit immediate value
to be added.
For cases where the TOC offset is unusually large, I put in an assert instead
of generating instructions. The reasoning was TOC offsets of this size should
never occur so those code paths would never be tested. Also TOC offsets of
that size are likely an indication of a problem elsewhere.
Closes: #9612
Cherry pick of #9613 for the 0.21 release.