Not sure if it's another gcc unrolling bug. Using gcc 6.2.0
g++ -DHAVE_CONFIG_H -I. -I.. -Werror -Wall -I sql -I/sandbox/pkg/lib/include -I/sandbox/pkg/include -rdynamic -march=native -O3 -pipe -I/sandbox/pkg/include -MT apl-Bif_F12_SORT.o -MD -MP -MF .deps/ap l-Bif_F12_SORT.Tpo -c -o apl-Bif_F12_SORT.o `test -f 'Bif_F12_SORT.cc' || echo './'`Bif_F12_SORT.cc In file included from PrintBuffer.hh:28:0, from Cell.hh:27, from Value.hh:30, from Value.icc:24, from NamedObject.hh:25, from Function.hh:27, from PrimitiveFunction.hh:25, from Bif_F12_SORT.hh:25, from Bif_F12_SORT.cc:22: Shape.hh: In constructor ‘CollatingCache::CollatingCache(const Value&, const Cell*, ShapeItem)’: Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[7]’ may be used uninitialized in this function [-Werror=maybe-uninitialized] rho[rho_rho++] = len; volume *= len; } ^~~ Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[7]’ was declared here const CollatingCacheEntry entry(uni, A.get_shape()); ^~~~~ In file included from PrintBuffer.hh:28:0, from Cell.hh:27, from Value.hh:30, from Value.icc:24, from NamedObject.hh:25, from Function.hh:27, from PrimitiveFunction.hh:25, from Bif_F12_SORT.hh:25, from Bif_F12_SORT.cc:22: Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[6]’ may be used uninitialized in this function [-Werror=maybe-uninitialized] rho[rho_rho++] = len; volume *= len; } ^~~ Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[6]’ was declared here const CollatingCacheEntry entry(uni, A.get_shape()); ^~~~~ In file included from PrintBuffer.hh:28:0, from Cell.hh:27, from Value.hh:30, from Value.icc:24, from NamedObject.hh:25, from Function.hh:27, from PrimitiveFunction.hh:25, from Bif_F12_SORT.hh:25, from Bif_F12_SORT.cc:22: Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[5]’ may be used uninitialized in this function [-Werror=maybe-uninitialized] rho[rho_rho++] = len; volume *= len; } ^~~ Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[5]’ was declared here const CollatingCacheEntry entry(uni, A.get_shape()); ^~~~~ In file included from PrintBuffer.hh:28:0, from Cell.hh:27, from Value.hh:30, from Value.icc:24, from NamedObject.hh:25, from Function.hh:27, from PrimitiveFunction.hh:25, from Bif_F12_SORT.hh:25, from Bif_F12_SORT.cc:22: Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[4]’ may be used uninitialized in this function [-Werror=maybe-uninitialized] rho[rho_rho++] = len; volume *= len; } ^~~ Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[4]’ was declared here const CollatingCacheEntry entry(uni, A.get_shape()); ^~~~~ In file included from PrintBuffer.hh:28:0, from Cell.hh:27, from Value.hh:30, from Value.icc:24, from NamedObject.hh:25, from Function.hh:27, from PrimitiveFunction.hh:25, from Bif_F12_SORT.hh:25, from Bif_F12_SORT.cc:22: Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[3]’ may be used uninitialized in this function [-Werror=maybe-uninitialized] rho[rho_rho++] = len; volume *= len; } ^~~ Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[3]’ was declared here const CollatingCacheEntry entry(uni, A.get_shape()); ^~~~~ In file included from PrintBuffer.hh:28:0, from Cell.hh:27, from Value.hh:30, from Value.icc:24, from NamedObject.hh:25, from Function.hh:27, from PrimitiveFunction.hh:25, from Bif_F12_SORT.hh:25, from Bif_F12_SORT.cc:22: Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[2]’ may be used uninitialized in this function [-Werror=maybe-uninitialized] rho[rho_rho++] = len; volume *= len; } ^~~ Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[2]’ was declared here const CollatingCacheEntry entry(uni, A.get_shape()); ^~~~~ In file included from PrintBuffer.hh:28:0, from Cell.hh:27, from Value.hh:30, from Value.icc:24, from NamedObject.hh:25, from Function.hh:27, from PrimitiveFunction.hh:25, from Bif_F12_SORT.hh:25, from Bif_F12_SORT.cc:22: Shape.hh:143:43: error: ‘*((void*)(& entry)+8).Shape::rho[1]’ may be used uninitialized in this function [-Werror=maybe-uninitialized] rho[rho_rho++] = len; volume *= len; } ^~~ Bif_F12_SORT.cc:56:36: note: ‘*((void*)(& entry)+8).Shape::rho[1]’ was declared here const CollatingCacheEntry entry(uni, A.get_shape()); ^~~~~ cc1plus: all warnings being treated as errors make[3]: *** [apl-Bif_F12_SORT.o] Error 1