From: Matthew Fortune Date: Wed, 22 Feb 2017 17:20:14 +0000 (+0000) Subject: Support WORD_REGISTER_OPERATIONS requirements in simplify_operand_subreg X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=198075e1c94ef8f9ecc31c9d4698b0761aab7d8c;p=gcc.git Support WORD_REGISTER_OPERATIONS requirements in simplify_operand_subreg gcc/ PR target/78660 * lra-constraints.c (simplify_operand_subreg): Handle WORD_REGISTER_OPERATIONS targets. From-SVN: r245655 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 7585f37940b..40a1d1f488a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-02-22 Matthew Fortune + + PR target/78660 + * lra-constraints.c (simplify_operand_subreg): Handle + WORD_REGISTER_OPERATIONS targets. + 2017-02-22 Jakub Jelinek PR target/70465 diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c index 35539a9cd99..224a9560c56 100644 --- a/gcc/lra-constraints.c +++ b/gcc/lra-constraints.c @@ -1541,11 +1541,22 @@ simplify_operand_subreg (int nop, machine_mode reg_mode) subregs as we don't substitute such equiv memory (see processing equivalences in function lra_constraints) and because for spilled pseudos we allocate stack memory enough for the biggest - corresponding paradoxical subreg. */ - if (!(MEM_ALIGN (subst) < GET_MODE_ALIGNMENT (mode) - && SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (subst))) - || (MEM_ALIGN (reg) < GET_MODE_ALIGNMENT (innermode) - && SLOW_UNALIGNED_ACCESS (innermode, MEM_ALIGN (reg)))) + corresponding paradoxical subreg. + + However, do not blindly simplify a (subreg (mem ...)) for + WORD_REGISTER_OPERATIONS targets as this may lead to loading junk + data into a register when the inner is narrower than outer or + missing important data from memory when the inner is wider than + outer. This rule only applies to modes that are no wider than + a word. */ + if (!(GET_MODE_PRECISION (mode) != GET_MODE_PRECISION (innermode) + && GET_MODE_SIZE (mode) <= UNITS_PER_WORD + && GET_MODE_SIZE (innermode) <= UNITS_PER_WORD + && WORD_REGISTER_OPERATIONS) + && (!(MEM_ALIGN (subst) < GET_MODE_ALIGNMENT (mode) + && SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (subst))) + || (MEM_ALIGN (reg) < GET_MODE_ALIGNMENT (innermode) + && SLOW_UNALIGNED_ACCESS (innermode, MEM_ALIGN (reg))))) return true; *curr_id->operand_loc[nop] = operand;