Improve handling of constants where its upper and lower 32-bit halves are the same and have negative values.
e.g. for: unsigned long f (void) { return 0xf0f0f0f0f0f0f0f0UL; } Without the patch: li a0,-252645376 addi a0,a0,240 li a5,-252645376 addi a5,a5,241 slli a5,a5,32 add a0,a5,a0 With the patch: li a5,252645376 addi a5,a5,-241 slli a0,a5,32 add a0,a0,a5 xori a0,a0,-1 gcc/ChangeLog: * config/riscv/riscv.cc (riscv_split_integer_cost): Adjust the cost of negative repeating constants. (riscv_split_integer): Handle negative repeating constants. gcc/testsuite/ChangeLog: * gcc.target/riscv/synthesis-11.c: New test. --- gcc/config/riscv/riscv.cc | 25 +++++++++++++---- gcc/testsuite/gcc.target/riscv/synthesis-11.c | 28 +++++++++++++++++++ 2 files changed, 47 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gcc.target/riscv/synthesis-11.c diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc index d03e51f3a68..b963a57881e 100644 --- a/gcc/config/riscv/riscv.cc +++ b/gcc/config/riscv/riscv.cc @@ -1242,8 +1242,8 @@ static int riscv_split_integer_cost (HOST_WIDE_INT val) { int cost; - unsigned HOST_WIDE_INT loval = sext_hwi (val, 32); - unsigned HOST_WIDE_INT hival = sext_hwi ((val - loval) >> 32, 32); + unsigned HOST_WIDE_INT loval = val & 0xffffffff; + unsigned HOST_WIDE_INT hival = (val & ~loval) >> 32; struct riscv_integer_op codes[RISCV_MAX_INTEGER_OPS]; /* This routine isn't used by pattern conditions, so whether or @@ -1254,6 +1254,8 @@ riscv_split_integer_cost (HOST_WIDE_INT val) cost = 2 + riscv_build_integer (codes, loval, VOIDmode, allow_new_pseudos); if (loval != hival) cost += riscv_build_integer (codes, hival, VOIDmode, allow_new_pseudos); + else if ((loval & 0x80000000) != 0) + cost = 3 + riscv_build_integer (codes, ~loval & 0xffffffff, VOIDmode, allow_new_pseudos); return cost; } @@ -1276,11 +1278,16 @@ riscv_integer_cost (HOST_WIDE_INT val, bool allow_new_pseudos) static rtx riscv_split_integer (HOST_WIDE_INT val, machine_mode mode) { - unsigned HOST_WIDE_INT loval = sext_hwi (val, 32); - unsigned HOST_WIDE_INT hival = sext_hwi ((val - loval) >> 32, 32); + unsigned HOST_WIDE_INT loval = val & 0xffffffff; + unsigned HOST_WIDE_INT hival = (val & ~loval) >> 32; rtx hi = gen_reg_rtx (mode), lo = gen_reg_rtx (mode); + rtx x = gen_reg_rtx (mode); + bool eq_neg = (loval == hival) && ((loval & 0x80000000) != 0); - riscv_move_integer (lo, lo, loval, mode); + if (eq_neg) + riscv_move_integer (lo, lo, ~loval & 0xffffffff, mode); + else + riscv_move_integer (lo, lo, loval, mode); if (loval == hival) hi = gen_rtx_ASHIFT (mode, lo, GEN_INT (32)); @@ -1291,7 +1298,13 @@ riscv_split_integer (HOST_WIDE_INT val, machine_mode mode) } hi = force_reg (mode, hi); - return gen_rtx_PLUS (mode, hi, lo); + x = gen_rtx_PLUS (mode, hi, lo); + if (eq_neg) + { + x = force_reg (mode, x); + x = gen_rtx_XOR (mode, x, GEN_INT (-1)); + } + return x; } /* Return true if X is a thread-local symbol. */ diff --git a/gcc/testsuite/gcc.target/riscv/synthesis-11.c b/gcc/testsuite/gcc.target/riscv/synthesis-11.c new file mode 100644 index 00000000000..89e48edb2d1 --- /dev/null +++ b/gcc/testsuite/gcc.target/riscv/synthesis-11.c @@ -0,0 +1,28 @@ +/* { dg-do compile } */ +/* { dg-require-effective-target rv64 } */ +/* We aggressively skip as we really just need to test the basic synthesis + which shouldn't vary based on the optimization level. -O1 seems to work + and eliminates the usual sources of extraneous dead code that would throw + off the counts. */ +/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-O2" "-O3" "-Os" "-Oz" "-flto" } } */ +/* { dg-options "-march=rv64gc" } */ + +/* Rather than test for a specific synthesis of all these constants or + having thousands of tests each testing one variant, we just test the + total number of instructions. + + This isn't expected to change much and any change is worthy of a look. */ +/* { dg-final { scan-assembler-times "\\t(add|addi|bseti|li|pack|ret|sh1add|sh2add|sh3add|slli|srli|xori)" 60 } } */ + + + +unsigned long foo_0xf857f2def857f2de(void) { return 0xf857f2def857f2deUL; } +unsigned long foo_0x99660e6399660e63(void) { return 0x99660e6399660e63UL; } +unsigned long foo_0x937f1b75937f1b75(void) { return 0x937f1b75937f1b75UL; } +unsigned long foo_0xb5019fa0b5019fa0(void) { return 0xb5019fa0b5019fa0UL; } +unsigned long foo_0xb828e6c1b828e6c1(void) { return 0xb828e6c1b828e6c1UL; } +unsigned long foo_0x839d87e9839d87e9(void) { return 0x839d87e9839d87e9UL; } +unsigned long foo_0xc29617c1c29617c1(void) { return 0xc29617c1c29617c1UL; } +unsigned long foo_0xa4118119a4118119(void) { return 0xa4118119a4118119UL; } +unsigned long foo_0x8c01df7d8c01df7d(void) { return 0x8c01df7d8c01df7dUL; } +unsigned long foo_0xf0e23d6bf0e23d6b(void) { return 0xf0e23d6bf0e23d6bUL; } -- 2.42.0