This patch enhances the effectiveness of the previously posted one: "xtensa: Optimize bitwise AND operation with some specific forms of constants".
/* example */ extern void foo(int); void test(int a) { if ((a & (-1U << 8)) == (128 << 8)) /* 0 or one of "b4const" */ foo(a); } ;; before .global test test: movi a3, -0x100 movi.n a4, 1 and a3, a2, a3 slli a4, a4, 15 bne a3, a4, .L3 j.l foo, a9 .L1: ret.n ;; after .global test test: srli a3, a2, 8 bnei a3, 128, .L1 j.l foo, a9 .L1: ret.n gcc/ChangeLog: * config/xtensa/xtensa.md (*masktrue_const_pow2_minus_one, *masktrue_const_negative_pow2, *masktrue_const_shifted_mask): If the immediate for bitwise AND is represented as '-(1 << N)', decrease the lower bound of N from 12 to 1. And the other immediate for conditional branch is now no longer limited to zero, but also one of some positive integers. Finally, remove the checks of some conditions, because the comparison expressions that don't satisfy such checks are determined as compile-time constants and thus will be optimized away before RTL expansion. --- gcc/config/xtensa/xtensa.md | 73 ++++++++++++++++++++++--------------- 1 file changed, 44 insertions(+), 29 deletions(-) diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md index 6a58d3e2776..c02f1a56641 100644 --- a/gcc/config/xtensa/xtensa.md +++ b/gcc/config/xtensa/xtensa.md @@ -1716,63 +1716,78 @@ (define_insn_and_split "*masktrue_const_pow2_minus_one" [(set (pc) - (if_then_else (match_operator 3 "boolean_operator" + (if_then_else (match_operator 4 "boolean_operator" [(and:SI (match_operand:SI 0 "register_operand" "r") (match_operand:SI 1 "const_int_operand" "i")) - (const_int 0)]) - (label_ref (match_operand 2 "" "")) + (match_operand:SI 2 "const_int_operand" "i")]) + (label_ref (match_operand 3 "" "")) (pc)))] - "IN_RANGE (exact_log2 (INTVAL (operands[1]) + 1), 17, 31)" + "IN_RANGE (exact_log2 (INTVAL (operands[1]) + 1), 17, 31) + /* && (~INTVAL (operands[1]) & INTVAL (operands[2])) == 0 // can be omitted */ + && xtensa_b4const_or_zero (INTVAL (operands[2]) << (32 - floor_log2 (INTVAL (operands[1]) + 1)))" "#" "&& can_create_pseudo_p ()" - [(set (match_dup 4) + [(set (match_dup 5) (ashift:SI (match_dup 0) (match_dup 1))) (set (pc) - (if_then_else (match_op_dup 3 - [(match_dup 4) - (const_int 0)]) - (label_ref (match_dup 2)) + (if_then_else (match_op_dup 4 + [(match_dup 5) + (match_dup 2)]) + (label_ref (match_dup 3)) (pc)))] { - operands[1] = GEN_INT (32 - floor_log2 (INTVAL (operands[1]) + 1)); - operands[4] = gen_reg_rtx (SImode); + int shift = 32 - floor_log2 (INTVAL (operands[1]) + 1); + operands[1] = GEN_INT (shift); + operands[2] = GEN_INT (INTVAL (operands[2]) << shift); + operands[5] = gen_reg_rtx (SImode); } [(set_attr "type" "jump") (set_attr "mode" "none") (set (attr "length") - (if_then_else (match_test "TARGET_DENSITY - && INTVAL (operands[1]) == 0x7FFFFFFF") - (const_int 5) - (const_int 6)))]) + (if_then_else (match_test "(TARGET_DENSITY && INTVAL (operands[1]) == 0x7FFFFFFF) + && INTVAL (operands[2]) == 0") + (const_int 4) + (if_then_else (match_test "TARGET_DENSITY + && (INTVAL (operands[1]) == 0x7FFFFFFF + || INTVAL (operands[2]) == 0)") + (const_int 5) + (const_int 6))))]) (define_insn_and_split "*masktrue_const_negative_pow2" [(set (pc) - (if_then_else (match_operator 3 "boolean_operator" + (if_then_else (match_operator 4 "boolean_operator" [(and:SI (match_operand:SI 0 "register_operand" "r") (match_operand:SI 1 "const_int_operand" "i")) - (const_int 0)]) - (label_ref (match_operand 2 "" "")) + (match_operand:SI 2 "const_int_operand" "i")]) + (label_ref (match_operand 3 "" "")) (pc)))] - "IN_RANGE (exact_log2 (-INTVAL (operands[1])), 12, 30)" + "IN_RANGE (exact_log2 (-INTVAL (operands[1])), 1, 30) + /* && (~INTVAL (operands[1]) & INTVAL (operands[2])) == 0 // can be omitted */ + && xtensa_b4const_or_zero (INTVAL (operands[2]) >> floor_log2 (-INTVAL (operands[1])))" "#" "&& can_create_pseudo_p ()" - [(set (match_dup 4) + [(set (match_dup 5) (lshiftrt:SI (match_dup 0) (match_dup 1))) (set (pc) - (if_then_else (match_op_dup 3 - [(match_dup 4) - (const_int 0)]) - (label_ref (match_dup 2)) + (if_then_else (match_op_dup 4 + [(match_dup 5) + (match_dup 2)]) + (label_ref (match_dup 3)) (pc)))] { - operands[1] = GEN_INT (floor_log2 (-INTVAL (operands[1]))); - operands[4] = gen_reg_rtx (SImode); + int shift = floor_log2 (-INTVAL (operands[1])); + operands[1] = GEN_INT (shift); + operands[2] = GEN_INT (INTVAL (operands[2]) >> shift); + operands[5] = gen_reg_rtx (SImode); } [(set_attr "type" "jump") (set_attr "mode" "none") - (set_attr "length" "6")]) + (set (attr "length") + (if_then_else (match_test "TARGET_DENSITY && INTVAL (operands[2]) == 0") + (const_int 5) + (const_int 6)))]) (define_insn_and_split "*masktrue_const_shifted_mask" [(set (pc) @@ -1782,8 +1797,8 @@ (match_operand:SI 2 "const_int_operand" "i")]) (label_ref (match_operand 3 "" "")) (pc)))] - "(INTVAL (operands[2]) & ((1 << ctz_hwi (INTVAL (operands[1]))) - 1)) == 0 - && xtensa_b4const_or_zero ((uint32_t)INTVAL (operands[2]) >> ctz_hwi (INTVAL (operands[1])))" + "/* (INTVAL (operands[2]) & ((1 << ctz_hwi (INTVAL (operands[1]))) - 1)) == 0 // can be omitted + && */ xtensa_b4const_or_zero ((uint32_t)INTVAL (operands[2]) >> ctz_hwi (INTVAL (operands[1])))" "#" "&& can_create_pseudo_p ()" [(set (match_dup 6) -- 2.20.1