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loop-unroll.c (analyze_insn_to_expand_var): Accept
* loop-unroll.c (analyze_insn_to_expand_var): Accept * accumulation via FMA if unsafe math. (insert_var_expansion_initialization): Handle FMA. (combine_var_copies_in_loop_exit): Likewise. From-SVN: r166781
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Richard Henderson
Richard Henderson
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f19f1e5ef0
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531e5376aa
@ -1,3 +1,10 @@
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2010-11-15 Richard Henderson <rth@redhat.com>
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* loop-unroll.c (analyze_insn_to_expand_var): Accept accumulation
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via FMA if unsafe math.
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(insert_var_expansion_initialization): Handle FMA.
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(combine_var_copies_in_loop_exit): Likewise.
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2010-11-15 Richard Henderson <rth@redhat.com>
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* config.gcc [ia64-*] (extra_options): Add fused-madd.opt.
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@ -1616,10 +1616,10 @@ reset_debug_uses_in_loop (struct loop *loop, rtx reg, int debug_uses)
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static struct var_to_expand *
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analyze_insn_to_expand_var (struct loop *loop, rtx insn)
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{
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rtx set, dest, src, op1, op2, something;
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rtx set, dest, src;
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struct var_to_expand *ves;
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enum machine_mode mode1, mode2;
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unsigned accum_pos;
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enum rtx_code code;
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int debug_uses = 0;
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set = single_set (insn);
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@ -1628,12 +1628,20 @@ analyze_insn_to_expand_var (struct loop *loop, rtx insn)
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dest = SET_DEST (set);
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src = SET_SRC (set);
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code = GET_CODE (src);
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if (GET_CODE (src) != PLUS
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&& GET_CODE (src) != MINUS
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&& GET_CODE (src) != MULT)
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if (code != PLUS && code != MINUS && code != MULT && code != FMA)
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return NULL;
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if (FLOAT_MODE_P (GET_MODE (dest)))
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{
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if (!flag_associative_math)
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return NULL;
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/* In the case of FMA, we're also changing the rounding. */
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if (code == FMA && !flag_unsafe_math_optimizations)
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return NULL;
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}
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/* Hmm, this is a bit paradoxical. We know that INSN is a valid insn
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in MD. But if there is no optab to generate the insn, we can not
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perform the variable expansion. This can happen if an MD provides
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@ -1643,54 +1651,57 @@ analyze_insn_to_expand_var (struct loop *loop, rtx insn)
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So we check have_insn_for which looks for an optab for the operation
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in SRC. If it doesn't exist, we can't perform the expansion even
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though INSN is valid. */
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if (!have_insn_for (GET_CODE (src), GET_MODE (src)))
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if (!have_insn_for (code, GET_MODE (src)))
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return NULL;
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op1 = XEXP (src, 0);
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op2 = XEXP (src, 1);
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if (!REG_P (dest)
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&& !(GET_CODE (dest) == SUBREG
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&& REG_P (SUBREG_REG (dest))))
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return NULL;
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if (rtx_equal_p (dest, op1))
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/* Find the accumulator use within the operation. */
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if (code == FMA)
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{
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/* We only support accumulation via FMA in the ADD position. */
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if (!rtx_equal_p (dest, XEXP (src, 2)))
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return NULL;
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accum_pos = 2;
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}
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else if (rtx_equal_p (dest, XEXP (src, 0)))
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accum_pos = 0;
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else if (rtx_equal_p (dest, op2))
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accum_pos = 1;
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else if (rtx_equal_p (dest, XEXP (src, 1)))
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{
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/* The method of expansion that we are using; which includes the
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initialization of the expansions with zero and the summation of
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the expansions at the end of the computation will yield wrong
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results for (x = something - x) thus avoid using it in that case. */
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if (code == MINUS)
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return NULL;
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accum_pos = 1;
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}
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else
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return NULL;
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/* The method of expansion that we are using; which includes
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the initialization of the expansions with zero and the summation of
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the expansions at the end of the computation will yield wrong results
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for (x = something - x) thus avoid using it in that case. */
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if (accum_pos == 1
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&& GET_CODE (src) == MINUS)
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return NULL;
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something = (accum_pos == 0) ? op2 : op1;
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if (rtx_referenced_p (dest, something))
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/* It must not otherwise be used. */
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if (code == FMA)
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{
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if (rtx_referenced_p (dest, XEXP (src, 0))
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|| rtx_referenced_p (dest, XEXP (src, 1)))
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return NULL;
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}
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else if (rtx_referenced_p (dest, XEXP (src, 1 - accum_pos)))
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return NULL;
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/* It must be used in exactly one insn. */
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if (!referenced_in_one_insn_in_loop_p (loop, dest, &debug_uses))
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return NULL;
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mode1 = GET_MODE (dest);
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mode2 = GET_MODE (something);
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if ((FLOAT_MODE_P (mode1)
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|| FLOAT_MODE_P (mode2))
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&& !flag_associative_math)
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return NULL;
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if (dump_file)
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{
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fprintf (dump_file,
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"\n;; Expanding Accumulator ");
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print_rtl (dump_file, dest);
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fprintf (dump_file, "\n");
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}
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{
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fprintf (dump_file, "\n;; Expanding Accumulator ");
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print_rtl (dump_file, dest);
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fprintf (dump_file, "\n");
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}
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if (debug_uses)
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/* Instead of resetting the debug insns, we could replace each
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@ -2123,22 +2134,33 @@ insert_var_expansion_initialization (struct var_to_expand *ve,
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return;
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start_sequence ();
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if (ve->op == PLUS || ve->op == MINUS)
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FOR_EACH_VEC_ELT (rtx, ve->var_expansions, i, var)
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{
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if (honor_signed_zero_p)
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zero_init = simplify_gen_unary (NEG, mode, CONST0_RTX (mode), mode);
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else
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zero_init = CONST0_RTX (mode);
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switch (ve->op)
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{
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case FMA:
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/* Note that we only accumulate FMA via the ADD operand. */
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case PLUS:
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case MINUS:
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FOR_EACH_VEC_ELT (rtx, ve->var_expansions, i, var)
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{
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if (honor_signed_zero_p)
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zero_init = simplify_gen_unary (NEG, mode, CONST0_RTX (mode), mode);
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else
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zero_init = CONST0_RTX (mode);
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emit_move_insn (var, zero_init);
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}
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break;
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emit_move_insn (var, zero_init);
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}
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else if (ve->op == MULT)
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FOR_EACH_VEC_ELT (rtx, ve->var_expansions, i, var)
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{
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zero_init = CONST1_RTX (GET_MODE (var));
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emit_move_insn (var, zero_init);
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}
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case MULT:
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FOR_EACH_VEC_ELT (rtx, ve->var_expansions, i, var)
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{
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zero_init = CONST1_RTX (GET_MODE (var));
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emit_move_insn (var, zero_init);
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}
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break;
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default:
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gcc_unreachable ();
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}
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seq = get_insns ();
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end_sequence ();
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@ -2165,18 +2187,24 @@ combine_var_copies_in_loop_exit (struct var_to_expand *ve, basic_block place)
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return;
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start_sequence ();
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if (ve->op == PLUS || ve->op == MINUS)
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FOR_EACH_VEC_ELT (rtx, ve->var_expansions, i, var)
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{
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sum = simplify_gen_binary (PLUS, GET_MODE (ve->reg),
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var, sum);
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}
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else if (ve->op == MULT)
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FOR_EACH_VEC_ELT (rtx, ve->var_expansions, i, var)
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{
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sum = simplify_gen_binary (MULT, GET_MODE (ve->reg),
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var, sum);
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}
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switch (ve->op)
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{
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case FMA:
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/* Note that we only accumulate FMA via the ADD operand. */
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case PLUS:
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case MINUS:
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FOR_EACH_VEC_ELT (rtx, ve->var_expansions, i, var)
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sum = simplify_gen_binary (PLUS, GET_MODE (ve->reg), var, sum);
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break;
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case MULT:
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FOR_EACH_VEC_ELT (rtx, ve->var_expansions, i, var)
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sum = simplify_gen_binary (MULT, GET_MODE (ve->reg), var, sum);
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break;
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default:
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gcc_unreachable ();
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}
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expr = force_operand (sum, ve->reg);
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if (expr != ve->reg)
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