https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89540
Bug ID: 89540
Summary: roundq(x) returning value with non-zero fractional
part
Product: gcc
Version: 8.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libquadmath
Assignee: unassigned at gcc dot gnu.org
Reporter: andres_takach at mentor dot com
Target Milestone: ---
Created attachment 45859
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45859&action=edit
Test: c++ round_bug.cxx -lquadmath
roundq should return an integer value (no fractional part), but it returns
values with fractional part. The incorrect behavior seems to occur when values
are big enough ( 2^31).
The testcase has x = 2^31 + 0.5. In this case roundq(x) returns x, instead of
2^31 + 1.
To exercise:
c++ round_bug.cxx -lquadmath
The output is (x, and roundq(x) are printed in both raw hex and decimal):
401e0000000100000000000000000000
2147483648.50000000000000000000000000000000000000000000000000
roundq(x) returns a value with fractional part
401e0000000100000000000000000000
2147483648.50000000000000000000000000000000000000000000000000
Incorrect behavior has also been confirmed with 6.2.0 and 4.9.2.
