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
