[PATCH v1 0/3] Support unsigned scalar SAT_MUL form 2

[pan2 . li]

From: Pan Li <pan2...@intel.com>

This patch would like to try to match the the unsigned
SAT_MUL form 2, aka below:

  #define DEF_SAT_U_MUL_FMT_2(T)               \
  T __attribute__((noinline))                  \
  sat_u_mul_##T##_fmt_2 (T a, T b)             \
  {                                            \
    T result;                                  \
    if (__builtin_mul_overflow(a, b, &result)) \
      return -1;                               \
    else                                       \
      return result;                           \
  }

While T is uint8_t, uint16_t, uint32_t and uint64_t.

Before this series if backend implemented usmul, we have:
  _6 = .MUL_OVERFLOW (a_4(D), b_5(D));
  _2 = IMAGPART_EXPR <_6>;
  if (_2 != 0)
    goto <bb 4>; [35.00%]
  else
    goto <bb 3>; [65.00%]

  <bb 3> [local count: 697932184]:
  _1 = REALPART_EXPR <_6>;

  <bb 4> [local count: 1073741824]:
  # _3 = PHI <18446744073709551615(2), _1(3)>

After this series if backend implemented usmul, we have:
  _3 = .SAT_MUL (a_4(D), b_5(D));

The below test suites are passed for this patch:
1. The rv64gcv fully regression tests.
2. The x86 bootstrap tests.
3. The x86 fully regression tests.

Pan Li (3):
  Match: Add form 2 for unsigned SAT_MUL
  Widening-Mul: Support unsigned scalar SAT_MUL 2
  RISC-V: Add testcase for scalar unsigned SAT_MUL form 2

 gcc/match.pd                                  | 12 +++++++
 .../gcc.target/riscv/sat/sat_arith.h          | 15 ++++++++
 .../gcc.target/riscv/sat/sat_u_mul-3-u16.c    | 11 ++++++
 .../gcc.target/riscv/sat/sat_u_mul-3-u32.c    | 11 ++++++
 .../gcc.target/riscv/sat/sat_u_mul-3-u64.c    | 11 ++++++
 .../gcc.target/riscv/sat/sat_u_mul-3-u8.c     | 11 ++++++
 .../riscv/sat/sat_u_mul-run-3-u16.c           | 15 ++++++++
 .../riscv/sat/sat_u_mul-run-3-u32.c           | 15 ++++++++
 .../riscv/sat/sat_u_mul-run-3-u64.c           | 15 ++++++++
 .../gcc.target/riscv/sat/sat_u_mul-run-3-u8.c | 15 ++++++++
 gcc/tree-ssa-math-opts.cc                     | 36 ++++++++++++++++++-
 11 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/riscv/sat/sat_u_mul-3-u16.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/sat/sat_u_mul-3-u32.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/sat/sat_u_mul-3-u64.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/sat/sat_u_mul-3-u8.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/sat/sat_u_mul-run-3-u16.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/sat/sat_u_mul-run-3-u32.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/sat/sat_u_mul-run-3-u64.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/sat/sat_u_mul-run-3-u8.c

-- 
2.43.0