Hi, This patch checks if a constant is possible to be built by "li;rldic". We only need to take care of "negative li", other forms do not need to check. For example, "negative lis" is just a "negative li" with an additional shift.
Bootstrap and regtest pass on ppc64{,le}. Is this ok for trunk? BR, Jeff (Jiufu) gcc/ChangeLog: * config/rs6000/rs6000.cc (can_be_built_by_li_and_rldic): New function. (rs6000_emit_set_long_const): Call can_be_built_by_li_and_rldic. gcc/testsuite/ChangeLog: * gcc.target/powerpc/const-build.c: Add more tests. --- gcc/config/rs6000/rs6000.cc | 61 ++++++++++++++++++- .../gcc.target/powerpc/const-build.c | 28 +++++++++ 2 files changed, 88 insertions(+), 1 deletion(-) diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc index 2a3fa733b45..cd04b6b5c82 100644 --- a/gcc/config/rs6000/rs6000.cc +++ b/gcc/config/rs6000/rs6000.cc @@ -10387,6 +10387,64 @@ can_be_built_by_li_lis_and_rldicr (HOST_WIDE_INT c, int *shift, return false; } +/* Check if value C can be built by 2 instructions: one is 'li', another is + rldic. + + If so, *SHIFT is set to the 'shift' operand of rldic; and *MASK is set + to the mask value about the 'mb' operand of rldic; and return true. + Return false otherwise. */ + +static bool +can_be_built_by_li_and_rldic (HOST_WIDE_INT c, int *shift, HOST_WIDE_INT *mask) +{ + /* There are 49 successive ones in the negative value of 'li'. */ + int ones = 49; + + /* 1..1xx1..1: negative value of li --> 0..01..1xx0..0: + right bits are shifted as 0's, and left 1's(and x's) are cleaned. */ + int tz = ctz_hwi (c); + int lz = clz_hwi (c); + int middle_ones = clz_hwi (~(c << lz)); + if (tz + lz + middle_ones >= ones) + { + *mask = ((1LL << (HOST_BITS_PER_WIDE_INT - tz - lz)) - 1LL) << tz; + *shift = tz; + return true; + } + + /* 1..1xx1..1 --> 1..1xx0..01..1: some 1's(following x's) are cleaned. */ + int leading_ones = clz_hwi (~c); + int tailing_ones = ctz_hwi (~c); + int middle_zeros = ctz_hwi (c >> tailing_ones); + if (leading_ones + tailing_ones + middle_zeros >= ones) + { + *mask = ~(((1ULL << middle_zeros) - 1ULL) << tailing_ones); + *shift = tailing_ones + middle_zeros; + return true; + } + + /* xx1..1xx: --> xx0..01..1xx: some 1's(following x's) are cleaned. */ + /* Get the position for the first bit of successive 1. + The 24th bit would be in successive 0 or 1. */ + HOST_WIDE_INT low_mask = (1LL << 24) - 1LL; + int pos_first_1 = ((c & (low_mask + 1)) == 0) + ? clz_hwi (c & low_mask) + : HOST_BITS_PER_WIDE_INT - ctz_hwi (~(c | low_mask)); + middle_ones = clz_hwi (~c << pos_first_1); + middle_zeros = ctz_hwi (c >> (HOST_BITS_PER_WIDE_INT - pos_first_1)); + if (pos_first_1 < HOST_BITS_PER_WIDE_INT + && middle_ones + middle_zeros < HOST_BITS_PER_WIDE_INT + && middle_ones + middle_zeros >= ones) + { + *mask = ~(((1ULL << middle_zeros) - 1LL) + << (HOST_BITS_PER_WIDE_INT - pos_first_1)); + *shift = HOST_BITS_PER_WIDE_INT - pos_first_1 + middle_zeros; + return true; + } + + return false; +} + /* Subroutine of rs6000_emit_set_const, handling PowerPC64 DImode. Output insns to set DEST equal to the constant C as a series of lis, ori and shl instructions. */ @@ -10435,7 +10493,8 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c) } else if (can_be_built_by_li_lis_and_rotldi (c, &shift, &mask) || can_be_built_by_li_lis_and_rldicl (c, &shift, &mask) - || can_be_built_by_li_lis_and_rldicr (c, &shift, &mask)) + || can_be_built_by_li_lis_and_rldicr (c, &shift, &mask) + || can_be_built_by_li_and_rldic (c, &shift, &mask)) { temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode); unsigned HOST_WIDE_INT imm = (c | ~mask); diff --git a/gcc/testsuite/gcc.target/powerpc/const-build.c b/gcc/testsuite/gcc.target/powerpc/const-build.c index 8c209921d41..b503ee31c7c 100644 --- a/gcc/testsuite/gcc.target/powerpc/const-build.c +++ b/gcc/testsuite/gcc.target/powerpc/const-build.c @@ -82,6 +82,29 @@ lis_rldicr_12 (void) return 0x5310000ffffffff0LL; } +long long NOIPA +li_rldic_13 (void) +{ + return 0x000f853100000000LL; +} +long long NOIPA +li_rldic_14 (void) +{ + return 0xffff853100ffffffLL; +} + +long long NOIPA +li_rldic_15 (void) +{ + return 0x800000ffffffff31LL; +} + +long long NOIPA +li_rldic_16 (void) +{ + return 0x800000000fffff31LL; +} + struct fun arr[] = { {li_rotldi_1, 0x7531000000000LL}, {li_rotldi_2, 0x2100000000000064LL}, @@ -95,11 +118,16 @@ struct fun arr[] = { {li_rldicr_10, 0xffff8531fff00000LL}, {li_rldicr_11, 0x21fffffffff00000LL}, {lis_rldicr_12, 0x5310000ffffffff0LL}, + {li_rldic_13, 0x000f853100000000LL}, + {li_rldic_14, 0xffff853100ffffffLL}, + {li_rldic_15, 0x800000ffffffff31LL}, + {li_rldic_16, 0x800000000fffff31LL} }; /* { dg-final { scan-assembler-times {\mrotldi\M} 6 } } */ /* { dg-final { scan-assembler-times {\mrldicl\M} 3 } } */ /* { dg-final { scan-assembler-times {\mrldicr\M} 3 } } */ +/* { dg-final { scan-assembler-times {\mrldic\M} 4 } } */ int main () -- 2.39.1