https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98151
Bug ID: 98151
Summary: integer output gives different results with -O2 and
-O3
Product: gcc
Version: 10.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: bradley_bell at yahoo dot com
Target Milestone: ---
Created attachment 49688
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49688&action=edit
bash shell script that creates the souce code, compiles, and runs the test
The attached bash script creates a c++ file called int_output.cpp, then
compiles and runs the program. If you run the script with no arguments you will
get the following usage message:
usage: ./int_output.sh print optimize
print: is either 0 or 1
optimize: is -O2 or -O3
If print is 0 and optimize is -O3, the test will fail.
Otherwise, the test will pass
The program starts with the maximum integer, uses a stringstream to convert it
to a string, and then converts it back to an integer. It then checks that the
result is the maximum integer; i.e., the integer it started with.
If print is 0 (1) the value of the starting and ending integers are printed.
The optimize argument determines the optimization level during the g++
compliation.
The only case that fails is when print is 0 and optimize is -O3.
In addition, if one uses clang++, instead of g++, all the cases give the
correct result.
