Hello! Attached patch fixes runtime comparison failure of 454.calculix due to wrong movement of vzeroupper in jump2 pass. It turns out, that can_move_insns_accross function does not special-case unspec_volatiles, so vzeroupper is allowed to pass various 256bit avx instructions.
The patch rejects moves of unspec_volatile insns in can_move_insn_accross. 2012-01-06 Uros Bizjak <ubiz...@gmail.com> PR rtl-optimization/55845 * df-problems.c (can_move_insns_across): Stop scanning at unspec_volatile source instruction. 2012-01-06 Uros Bizjak <ubiz...@gmail.com> Vladimir Yakovlev <vladimir.b.yakov...@intel.com> PR rtl-optimization/55845 * gcc.target/i386/pr55845.c: New test. Bootstrapped and regression tested on x86_64-pc-linux-gnu {,-m32} AVX target. OK for mainline and 4.7 branch? Uros.
Index: df-problems.c =================================================================== --- df-problems.c (revision 194945) +++ df-problems.c (working copy) @@ -3916,6 +3916,10 @@ can_move_insns_across (rtx from, rtx to, rtx acros break; if (NONDEBUG_INSN_P (insn)) { + /* Do not move unspec_volatile insns. */ + if (GET_CODE (PATTERN (insn)) == UNSPEC_VOLATILE) + break; + if (may_trap_or_fault_p (PATTERN (insn)) && (trapping_insns_in_across || other_branch_live != NULL)) break; Index: testsuite/gcc.target/i386/pr55845.c =================================================================== --- testsuite/gcc.target/i386/pr55845.c (revision 0) +++ testsuite/gcc.target/i386/pr55845.c (working copy) @@ -0,0 +1,39 @@ +/* { dg-do run } */ +/* { dg-require-effective-target avx } */ +/* { dg-options "-O3 -ffast-math -fschedule-insns -mavx -mvzeroupper" } */ + +#include "avx-check.h" + +#define N 100 + +double +__attribute__((noinline)) +foo (int size, double y[], double x[]) +{ + double sum = 0.0; + int i; + for (i = 0, sum = 0.; i < size; i++) + sum += y[i] * x[i]; + return (sum); +} + +static void +__attribute__ ((noinline)) +avx_test () +{ + double x[N]; + double y[N]; + double s; + int i; + + for (i = 0; i < N; i++) + { + x[i] = i; + y[i] = i; + } + + s = foo (N, y, x); + + if (s != 328350.0) + abort (); +}