From: Richard Sandiford Date: Sun, 22 Oct 2017 21:41:57 +0000 (+0000) Subject: SUBREG_PROMOTED_VAR_P handling in expand_direct_optab_fn X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b7753f75ea1644c3d18dcfaf9878fb5ec1460c6a;p=gcc.git SUBREG_PROMOTED_VAR_P handling in expand_direct_optab_fn This is needed by the later SVE LAST reductions, where an 8-bit or 16-bit result is zero- rather than sign-extended to 32 bits. I think it could occur in other situations too. 2017-09-19 Richard Sandiford Alan Hayward David Sherwood gcc/ * internal-fn.c (expand_direct_optab_fn): Don't assign directly to a SUBREG_PROMOTED_VAR. Co-Authored-By: Alan Hayward Co-Authored-By: David Sherwood From-SVN: r253992 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ebaf8b354cc..64ee44ec6f3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2017-10-22 Richard Sandiford + Alan Hayward + David Sherwood + + * internal-fn.c (expand_direct_optab_fn): Don't assign directly + to a SUBREG_PROMOTED_VAR. + 2017-10-22 Richard Sandiford Alan Hayward David Sherwood diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c index ce9e8bb75e9..94873c2948a 100644 --- a/gcc/internal-fn.c +++ b/gcc/internal-fn.c @@ -2606,7 +2606,15 @@ expand_direct_optab_fn (internal_fn fn, gcall *stmt, direct_optab optab, tree lhs = gimple_call_lhs (stmt); tree lhs_type = TREE_TYPE (lhs); rtx lhs_rtx = expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE); - create_output_operand (&ops[0], lhs_rtx, insn_data[icode].operand[0].mode); + + /* Do not assign directly to a promoted subreg, since there is no + guarantee that the instruction will leave the upper bits of the + register in the state required by SUBREG_PROMOTED_SIGN. */ + rtx dest = lhs_rtx; + if (GET_CODE (dest) == SUBREG && SUBREG_PROMOTED_VAR_P (dest)) + dest = NULL_RTX; + + create_output_operand (&ops[0], dest, insn_data[icode].operand[0].mode); for (unsigned int i = 0; i < nargs; ++i) {