Closed Bug 770630 Opened 13 years ago Closed 9 years ago

IonMonkey: Don't use ptest in emitDoubleToInt32 on x86/x64

Categories

(Core :: JavaScript Engine, defect)

Product:
Core
Component:
JavaScript Engine
Type:
defect
Priority:
Not set
Severity:
normal

Tracking

()

Status:
RESOLVED DUPLICATE of bug 995934

People

(Reporter: jandem, Unassigned)

References

(Blocks 1 open bug)

Details

(Whiteboard: [ion:t])

emitDoubleToInt32 emits ptest to check if a double is negative zero. Problem with this instruction is that it compares all 128 bits but the upper 64 bits may contain garbage. There's no correctness bug here since we will always bailout for -0, but it's possible we will unnecessarily bailout for +0 as well. The easiest fix is to use the non-SSE 4.1 code which uses movmskpd to extract the sign bit.
Assignee: general → nobody
Fixed in https://hg.mozilla.org/mozilla-central/rev/f4b188b044cc (bug 995934).
Status: NEW → RESOLVED
Closed: 9 years ago
Resolution: --- → DUPLICATE
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