Description of problem:
New version of gcc fails with "error: exponent has no digits"

Reproducer (test.cpp):
"
int main(){
 double x = 0xabcab.defdefP-10;
}
"

compiling with g++ -std=c++11 -o test test.cpp

With gcc-6.0.0-0.15.fc24 it works fine.

Version-Release number of selected component (if applicable):


How reproducible:
gcc-6.0.0-0.18.fc24

Actual results:
compile failure "error: exponent has no digits"

Expected results:
compilation success