https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63211
Bug ID: 63211 Summary: gcc.target/i386/avx2-*.c tests use broken type-punning Product: gcc Version: 4.9.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: testsuite Assignee: unassigned at gcc dot gnu.org Reporter: rguenth at gcc dot gnu.org Target: x86_64-*-*, i?86-*-* For example gcc.target/i386/avx2-vpblendd128-2.c does static void init_pblendd128 (int *src1, int *src2, int seed) { int i, sign = 1; for (i = 0; i < 4; i++) { src1[i] = (i + seed) * (i + seed) * sign; src2[i] = (i + seed + 20) * sign; sign = -sign; } } ... static void avx2_test (void) { union128i_d src1, src2, dst; int dst_ref[4]; int i; for (i = 0; i < NUM; i++) { init_pblendd128 (src1.a, src2.a, i); dst.x = _mm_blend_epi32 (src1.x, src2.x, MASK); which stores to src1.a/src2.a via a pointer and not a direct union access. This makes us optimize away the init_pblendd128 function after it being inlined. FAIL: gcc.target/i386/avx2-vpblendd128-2.c execution test FAIL: gcc.target/i386/avx2-vpblendd256-2.c execution test FAIL: gcc.target/i386/avx2-vpblendw-2.c execution test FAIL: gcc.target/i386/avx2-vpbroadcastd128-2.c execution test FAIL: gcc.target/i386/avx2-vpbroadcastd256-2.c execution test FAIL: gcc.target/i386/avx2-vpbroadcastw128-2.c execution test FAIL: gcc.target/i386/avx2-vpbroadcastw256-2.c execution test FAIL: gcc.target/i386/avx2-vpermd-2.c execution test FAIL: gcc.target/i386/avx2-vpermps-2.c execution test FAIL: gcc.target/i386/avx2-vpmaxsd-2.c execution test FAIL: gcc.target/i386/avx2-vpmaxsw-2.c execution test FAIL: gcc.target/i386/avx2-vpmaxud-2.c execution test FAIL: gcc.target/i386/avx2-vpmaxuw-2.c execution test FAIL: gcc.target/i386/avx2-vpminsd-2.c execution test FAIL: gcc.target/i386/avx2-vpminsw-2.c execution test FAIL: gcc.target/i386/avx2-vpminud-2.c execution test FAIL: gcc.target/i386/avx2-vpminuw-2.c execution test FAIL: gcc.target/i386/avx2-vpmuldq-2.c execution test FAIL: gcc.target/i386/avx2-vpmulhrsw-2.c execution test FAIL: gcc.target/i386/avx2-vpmulhuw-2.c execution test FAIL: gcc.target/i386/avx2-vpmulhw-2.c execution test FAIL: gcc.target/i386/avx2-vpmulld-2.c execution test FAIL: gcc.target/i386/avx2-vpmullw-2.c execution test FAIL: gcc.target/i386/avx2-vpmuludq-2.c execution test FAIL: gcc.target/i386/avx2-vpshufd-2.c execution test FAIL: gcc.target/i386/avx2-vpshufhw-2.c execution test FAIL: gcc.target/i386/avx2-vpshuflw-2.c execution test FAIL: gcc.target/i386/avx2-vpsignd-2.c execution test FAIL: gcc.target/i386/avx2-vpsignw-2.c execution test FAIL: gcc.target/i386/avx2-vpslld-2.c execution test FAIL: gcc.target/i386/avx2-vpsllvd128-2.c execution test FAIL: gcc.target/i386/avx2-vpsllvd256-2.c execution test FAIL: gcc.target/i386/avx2-vpsllw-2.c execution test FAIL: gcc.target/i386/avx2-vpsrad-2.c execution test FAIL: gcc.target/i386/avx2-vpsravd128-2.c execution test FAIL: gcc.target/i386/avx2-vpsravd256-2.c execution test FAIL: gcc.target/i386/avx2-vpsraw-2.c execution test FAIL: gcc.target/i386/avx2-vpsrld-2.c execution test FAIL: gcc.target/i386/avx2-vpsrlvd128-2.c execution test FAIL: gcc.target/i386/avx2-vpsrlvd256-2.c execution test FAIL: gcc.target/i386/avx2-vpsrlw-2.c execution test FAIL: gcc.target/i386/avx2-vpunpckhdq-2.c execution test FAIL: gcc.target/i386/avx2-vpunpckhwd-2.c execution test FAIL: gcc.target/i386/avx2-vpunpckldq-2.c execution test FAIL: gcc.target/i386/avx2-vpunpcklwd-2.c execution test the actual miscompile only happens if you apply the fix for PR40135, the testcases are broken nevertheless according to how type-punning through unions is supposed to work.