ifcvt.c (total_bb_rtx_cost): Rename function to cheap_bb_rtx_cost_p.
* ifcvt.c (total_bb_rtx_cost): Rename function to cheap_bb_rtx_cost_p. Take a max_cost argument to avoid scanning large blocks, by returning a Boolean instead of a total. Include the cost of a "fstp %st(0)" instruction required to pop dead values off of a register stack. From-SVN: r92352
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@ -1,3 +1,10 @@
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2004-12-18 Roger Sayle <roger@eyesopen.com>
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* ifcvt.c (total_bb_rtx_cost): Rename function to cheap_bb_rtx_cost_p.
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Take a max_cost argument to avoid scanning large blocks, by returning
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a Boolean instead of a total. Include the cost of a "fstp %st(0)"
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instruction required to pop dead values off of a register stack.
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2004-12-18 Roger Sayle <roger@eyesopen.com>
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PR middle-end/18548
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43
gcc/ifcvt.c
43
gcc/ifcvt.c
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@ -86,7 +86,7 @@ static bool life_data_ok;
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/* Forward references. */
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static int count_bb_insns (basic_block);
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static int total_bb_rtx_cost (basic_block);
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static bool cheap_bb_rtx_cost_p (basic_block, int);
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static rtx first_active_insn (basic_block);
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static rtx last_active_insn (basic_block, int);
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static basic_block block_fallthru (basic_block);
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@ -162,12 +162,12 @@ count_bb_insns (basic_block bb)
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return count;
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}
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/* Count the total insn_rtx_cost of non-jump active insns in BB.
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This function returns -1, if the cost of any instruction could
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not be estimated. */
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/* Determine whether the total insn_rtx_cost on non-jump insns in
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basic block BB is less than MAX_COST. This function returns
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false if the cost of any instruction could not be estimated. */
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static int
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total_bb_rtx_cost (basic_block bb)
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static bool
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cheap_bb_rtx_cost_p (basic_block bb, int max_cost)
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{
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int count = 0;
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rtx insn = BB_HEAD (bb);
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@ -178,18 +178,34 @@ total_bb_rtx_cost (basic_block bb)
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{
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int cost = insn_rtx_cost (PATTERN (insn));
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if (cost == 0)
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return -1;
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return false;
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/* If this instruction is the load or set of a "stack" register,
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such as a floating point register on x87, then the cost of
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speculatively executing this instruction needs to include
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the additional cost of popping this register off of the
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register stack. */
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#ifdef STACK_REGS
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{
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rtx set = single_set (insn);
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if (set && STACK_REG_P (SET_DEST (set)))
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cost += COSTS_N_INSNS (1);
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}
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#endif
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count += cost;
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if (count >= max_cost)
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return false;
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}
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else if (CALL_P (insn))
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return -1;
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return false;
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if (insn == BB_END (bb))
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break;
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insn = NEXT_INSN (insn);
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}
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return count;
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return true;
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}
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/* Return the first non-jump active insn in the basic block. */
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@ -2853,7 +2869,7 @@ find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
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{
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basic_block then_bb = then_edge->dest;
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basic_block else_bb = else_edge->dest, new_bb;
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int then_bb_index, bb_cost;
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int then_bb_index;
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/* If we are partitioning hot/cold basic blocks, we don't want to
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mess up unconditional or indirect jumps that cross between hot
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@ -2896,8 +2912,7 @@ find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
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test_bb->index, then_bb->index);
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/* THEN is small. */
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bb_cost = total_bb_rtx_cost (then_bb);
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if (bb_cost < 0 || bb_cost >= COSTS_N_INSNS (BRANCH_COST))
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if (! cheap_bb_rtx_cost_p (then_bb, COSTS_N_INSNS (BRANCH_COST)))
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return FALSE;
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/* Registers set are dead, or are predicable. */
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@ -2944,7 +2959,6 @@ find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
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basic_block then_bb = then_edge->dest;
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basic_block else_bb = else_edge->dest;
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edge else_succ;
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int bb_cost;
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rtx note;
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/* If we are partitioning hot/cold basic blocks, we don't want to
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@ -3001,8 +3015,7 @@ find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
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test_bb->index, else_bb->index);
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/* ELSE is small. */
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bb_cost = total_bb_rtx_cost (else_bb);
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if (bb_cost < 0 || bb_cost >= COSTS_N_INSNS (BRANCH_COST))
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if (! cheap_bb_rtx_cost_p (else_bb, COSTS_N_INSNS (BRANCH_COST)))
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return FALSE;
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/* Registers set are dead, or are predicable. */
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