Regressions on trunk at revision 271813 vs revision 271791

[H.J. Lu (Intel64 Core i7)]

New failures:
FAIL: gcc.dg/guality/pr48437.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  -DPREVENT_OPTIMIZATION line 14 i == 0
FAIL: gcc.dg/guality/pr48437.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  -DPREVENT_OPTIMIZATION line 14 i == 0
FAIL: gcc.dg/guality/pr48437.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects  -DPREVENT_OPTIMIZATION line 14 i == 0
FAIL: gcc.dg/guality/pr48437.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects  -DPREVENT_OPTIMIZATION line 14 i == 0
FAIL: g++.dg/cpp0x/noexcept15.C  -std=c++14 (test for excess errors)
FAIL: g++.dg/cpp0x/noexcept15.C  -std=c++14 (test for excess errors)

New passes: