https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96153
--- Comment #4 from Iain Buclaw <ibuclaw at gdcproject dot org> --- Created attachment 49006 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49006&action=edit inline memset (In reply to Iain Buclaw from comment #3) > (In reply to Rainer Orth from comment #2) > > The new test FAILs on 64-bit Solaris/SPARC: > > > > The test PASSes with -O0 and -Os, as well as with -m32. > > Thanks, I've checked Linux/SPARC64 and see the same thing. DSE is removing the call to memset as dead code, so the optimizer is not understanding the hint. Inlining the memset using a bunch of MEM_REFs yields the correct result, and infact the optimizer is able to fully const-fold the hash computation at -O3 so all assert contracts are removed. Though not sure about the approach, are there any pitfalls to this? This is what optimized trees look like at -O1 and -O2 levels, with comments inserted describing which bits are set. x86_64 -O1: // 0..128 = 0 MEM <uint128_t *> [(uint128_t *)&D.4244] = 0B; // 128..192 = 0 MEM[(ulong *)&D.4244 + 16B] = 0B; // 0..32 = 12 D.4244.payload = 12; // 128..160 = 4294967295 D.4244.hook.var2 = 4294967295; // 64..128 = 18446744073709551615 D.4244.hook.var1 = 18446744073709551615; x86_64 -O2: // 0..64 = 12 MEM <unsigned long> [(void *)&D.4244] = 12; // 64..128 = 18446744073709551615 D.4244.hook.var1 = 18446744073709551615; // 128..192 = 4294967295 MEM <unsigned long> [(void *)&D.4244 + 16B] = 4294967295; SPARC64 -O1: // 0..128 = 51539607552 MEM <uint128_t *> [(void *)&D.1048] = 51539607552B; // 64..128 = 18446744073709551615 MEM <ulong> [(void *)&D.1048 + 8B] = 18446744073709551615; // 128..192 = -4294967296 MEM <ulong *> [(void *)&D.1048 + 16B] = -4294967296B; SPARC -O2 // 0..128 = 51539607552 MEM <uint128_t *> [(void *)&D.1048] = 51539607552B; // 64..128 = 18446744073709551615 MEM <ulong> [(void *)&D.1048 + 8B] = 18446744073709551615; // 128..192 = -4294967296 MEM <ulong *> [(void *)&D.1048 + 16B] = -4294967296B; Both SPARC and x86_64 yield the same hash values. assert(-1444610504 != -1444610503); assert(-1444610503 == -1444610503);
