Widening-Mul: Fix one ICE for SAT_SUB matching operand checking

This patch would like to fix the following ICE for -O2 -m32 of x86_64.

during RTL pass: expand
JackMidiAsyncWaitQueue.cpp.cpp: In function 'void DequeueEvent(unsigned
int)':
JackMidiAsyncWaitQueue.cpp.cpp:3:6: internal compiler error: in
expand_fn_using_insn, at internal-fn.cc:263
    3 | void DequeueEvent(unsigned frame) {
      |      ^~~~~~~~~~~~
0x27b580d diagnostic_context::diagnostic_impl(rich_location*,
diagnostic_metadata const*, diagnostic_option_id, char const*,
__va_list_tag (*) [1], diagnostic_t)
        ???:0
0x27c4a3f internal_error(char const*, ...)
        ???:0
0x27b3994 fancy_abort(char const*, int, char const*)
        ???:0
0xf25ae5 expand_fn_using_insn(gcall*, insn_code, unsigned int, unsigned int)
        ???:0
0xf2a124 expand_direct_optab_fn(internal_fn, gcall*, optab_tag, unsigned int)
        ???:0
0xf2c87c expand_SAT_SUB(internal_fn, gcall*)
        ???:0

We allowed the operand convert when matching SAT_SUB in match.pd, to support
the zip benchmark SAT_SUB pattern.  Aka,

(convert? (minus (convert1? @0) (convert1? @1))) for below sample code.

void test (uint16_t *x, unsigned b, unsigned n)
{
  unsigned a = 0;
  register uint16_t *p = x;

  do {
    a = *--p;
    *p = (uint16_t)(a >= b ? a - b : 0); // Truncate after .SAT_SUB
  } while (--n);
}

The pattern match for SAT_SUB itself may also act on below scalar sample
code too.

unsigned long long GetTimeFromFrames(int);
unsigned long long GetMicroSeconds();

void DequeueEvent(unsigned frame) {
  long long frame_time = GetTimeFromFrames(frame);
  unsigned long long current_time = GetMicroSeconds();
  DequeueEvent(frame_time < current_time ? 0 : frame_time - current_time);
}

Aka:

uint32_t a = (uint32_t)SAT_SUB(uint64_t, uint64_t);

Then there will be a problem when ia32 or -m32 is given when compiling.
Because we only check the lhs (aka uint32_t) type is supported by ifn
instead of the operand (aka uint64_t).  Mostly DImode is disabled for
32 bits target like ia32 or rv32gcv, and then trigger ICE when expanding.

The below test suites are passed for this patch.
* The rv64gcv fully regression test.
* The x86 bootstrap test.
* The x86 fully regression test.

	PR middle-end/116814

gcc/ChangeLog:

	* tree-ssa-math-opts.cc (build_saturation_binary_arith_call): Make
	ifn is_supported type check based on operand instead of lhs.

gcc/testsuite/ChangeLog:

	* g++.dg/torture/pr116814-1.C: New test.

Signed-off-by: Pan Li <pan2.li@intel.com>